Ebbing Strength, Fading Power: Unveiling the Impact of Persistent Fatigue on Muscle Performance in COVID-19 Survivors

Abstract:

The total number of confirmed cases of COVID-19 caused by SARS-CoV-2 virus infection is over 621 million. Post-COVID-19 syndrome, also known as long COVID or long-haul COVID, refers to a persistent condition where individuals experience symptoms and health issues after the acute phase of COVID-19.

The aim of this study was to assess the strength and fatigue of skeletal muscles in people recovered from COVID-19. A total of 94 individuals took part in this cross-sectional study, with 45 participants (referred to as the Post-COVID Cohort, PCC) and 49 healthy age-matched volunteers (Healthy Control Cohort, HCC).

This research article uses the direct dynamometry method to provide a detailed analysis of post-COVID survivors’ strength and power characteristics. The Biodex System 4 Pro was utilized to evaluate muscle strength characteristics during the fatigue test. The fatigue work in extensors and flexors was significantly higher in the PCC.  The PCC also showed significantly less power in both extensors and flexors compared to the HCC.

In conclusion, this study provides compelling evidence of the impact of post-COVID-19 fatigue on muscle performance, highlighting the importance of considering these effects in the rehabilitation and care of individuals recovering from the virus. PCC achieved lower muscle strength values than HCC.

Source: Kowal M, Morgiel E, Winiarski S, Dymarek R, Bajer W, Madej M, Sebastian A, Madziarski M, Wedel N, Proc K, Madziarska K, Wiland P, Paprocka-Borowicz M. Ebbing Strength, Fading Power: Unveiling the Impact of Persistent Fatigue on Muscle Performance in COVID-19 Survivors. Sensors (Basel). 2024 Feb 15;24(4):1250. doi: 10.3390/s24041250. PMID: 38400407; PMCID: PMC10892381. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10892381/ (Full text)

Sex differences in symptomatology and immune profiles of Long COVID

Abstract:

Strong sex differences in the frequencies and manifestations of Long COVID (LC) have been reported with females significantly more likely than males to present with LC after acute SARS-CoV-2 infection1-7. However, whether immunological traits underlying LC differ between sexes, and whether such differences explain the differential manifestations of LC symptomology is currently unknown.

Here, we performed sex-based multi-dimensional immune-endocrine profiling of 165 individuals8 with and without LC in an exploratory, cross-sectional study to identify key immunological traits underlying biological sex differences in LC.

We found that female and male participants with LC experienced different sets of symptoms, and distinct patterns of organ system involvement, with female participants suffering from a higher symptom burden. Machine learning approaches identified differential sets of immune features that characterized LC in females and males. Males with LC had decreased frequencies of monocyte and DC populations, elevated NK cells, and plasma cytokines including IL-8 and TGF-β-family members.

Females with LC had increased frequencies of exhausted T cells, cytokine-secreting T cells, higher antibody reactivity to latent herpes viruses including EBV, HSV-2, and CMV, and lower testosterone levels than their control female counterparts. Testosterone levels were significantly associated with lower symptom burden in LC participants over sex designation.

These findings suggest distinct immunological processes of LC in females and males and illuminate the crucial role of immune-endocrine dysregulation in sex-specific pathology.

Source: Julio Silva, Takehiro Takahashi, Jamie Wood, Peiwen Lu, Sasha Tabachnikova, Jeffrey Gehlhausen, Kerrie Greene, Bornali Bhattacharjee, Valter Silva Monteiro, Carolina Lucas, Rahul Dhodapkar, Laura Tabacof, Mario Pena-Hernandez, Kathy Kamath, Tianyang Mao, Dayna Mccarthy, Ruslan Medzhitov, David van Dijk, Harlan Krumholz, Leying Guan, David Putrino, Akiko Iwasaki. Sex differences in symptomatology and immune profiles of Long COVID. medRxiv 2024.02.29.24303568; doi: https://doi.org/10.1101/2024.02.29.24303568 https://www.medrxiv.org/content/10.1101/2024.02.29.24303568v1 (Full study available as PDF file)

Cognition and Memory after Covid-19 in a Large Community Sample

Abstract:

Background: Cognitive symptoms after coronavirus disease 2019 (Covid-19), the disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), are well-recognized. Whether objectively measurable cognitive deficits exist and how long they persist are unclear.

Methods: We invited 800,000 adults in a study in England to complete an online assessment of cognitive function. We estimated a global cognitive score across eight tasks. We hypothesized that participants with persistent symptoms (lasting ≥12 weeks) after infection onset would have objectively measurable global cognitive deficits and that impairments in executive functioning and memory would be observed in such participants, especially in those who reported recent poor memory or difficulty thinking or concentrating (“brain fog”).

Results: Of the 141,583 participants who started the online cognitive assessment, 112,964 completed it. In a multiple regression analysis, participants who had recovered from Covid-19 in whom symptoms had resolved in less than 4 weeks or at least 12 weeks had similar small deficits in global cognition as compared with those in the no-Covid-19 group, who had not been infected with SARS-CoV-2 or had unconfirmed infection (-0.23 SD [95% confidence interval {CI}, -0.33 to -0.13] and -0.24 SD [95% CI, -0.36 to -0.12], respectively); larger deficits as compared with the no-Covid-19 group were seen in participants with unresolved persistent symptoms (-0.42 SD; 95% CI, -0.53 to -0.31). Larger deficits were seen in participants who had SARS-CoV-2 infection during periods in which the original virus or the B.1.1.7 variant was predominant than in those infected with later variants (e.g., -0.17 SD for the B.1.1.7 variant vs. the B.1.1.529 variant; 95% CI, -0.20 to -0.13) and in participants who had been hospitalized than in those who had not been hospitalized (e.g., intensive care unit admission, -0.35 SD; 95% CI, -0.49 to -0.20). Results of the analyses were similar to those of propensity-score-matching analyses. In a comparison of the group that had unresolved persistent symptoms with the no-Covid-19 group, memory, reasoning, and executive function tasks were associated with the largest deficits (-0.33 to -0.20 SD); these tasks correlated weakly with recent symptoms, including poor memory and brain fog. No adverse events were reported.

Conclusions: Participants with resolved persistent symptoms after Covid-19 had objectively measured cognitive function similar to that in participants with shorter-duration symptoms, although short-duration Covid-19 was still associated with small cognitive deficits after recovery. Longer-term persistence of cognitive deficits and any clinical implications remain uncertain. (Funded by the National Institute for Health and Care Research and others.).

Source: Hampshire A, Azor A, Atchison C, Trender W, Hellyer PJ, Giunchiglia V, Husain M, Cooke GS, Cooper E, Lound A, Donnelly CA, Chadeau-Hyam M, Ward H, Elliott P. Cognition and Memory after Covid-19 in a Large Community Sample. N Engl J Med. 2024 Feb 29;390(9):806-818. doi: 10.1056/NEJMoa2311330. PMID: 38416429. https://www.nejm.org/doi/10.1056/NEJMoa2311330 (Full text)

Severe COVID-19 and long COVID are associated with high expression of STING, cGAS and IFN-α

Abstract:

The cGAS-STING pathway appears to contribute to dysregulated inflammation during coronavirus disease 2019 (COVID-19); however, inflammatory factors related to long COVID are still being investigated.

In the present study, we evaluated the association of cGAS and STING gene expression levels and plasma IFN-α, TNF-α and IL-6 levels with COVID-19 severity in acute infection and long COVID, based on analysis of blood samples from 148 individuals, 87 with acute COVID-19 and 61 in the post-COVID-19 period.

Quantification of gene expression was performed by real-time PCR, and cytokine levels were quantified by ELISA and flow cytometry. In acute COVID-19, cGAS, STING, IFN-α, TNF-α, and IL-6 levels were higher in patients with severe disease than in those with nonsevere manifestations (p < 0.05). Long COVID was associated with elevated cGAS, STING and IFN-α levels (p < 0.05).

Activation of the cGAS-STING pathway may contribute to an intense systemic inflammatory state in severe COVID-19 and, after infection resolution, induce an autoinflammatory disease in some tissues, resulting in long COVID.

Source: Queiroz, M.A.F., Brito, W.R.S., Pereira, K.A.S. et al. Severe COVID-19 and long COVID are associated with high expression of STING, cGAS and IFN-α. Sci Rep 14, 4974 (2024). https://doi.org/10.1038/s41598-024-55696-0 https://www.nature.com/articles/s41598-024-55696-0 (Full text)

Clinical evidence of the link between gut microbiome and myalgic encephalomyelitis/chronic fatigue syndrome: a retrospective review

Abstract:

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a heterogeneous disorder with elusive causes, but most likely because of clinical and other biological factors. As a vital environmental factor, the gut microbiome is increasingly emphasized in various refractory diseases including ME/CFS. The present study is aimed to enhance our understanding of the relationship between the gut microbiome and ME/CFS through data analysis of various clinical studies.

We conducted a literature search in four databases (PubMed, Cochrane Library, Web of Science, and Google Scholar) until May 31, 2023. Our analysis encompassed 11 clinical studies with 553 ME/CFS patients and 480 healthy controls. A comparative analysis of meta data revealed a significant decrease in α-diversity and a noticeable change in β-diversity in the gut microbiome of ME/CFS patients compared to healthy controls.

The notable ratio of Firmicutes and Bacteroides was 2.3 times decreased, and also, there was a significant reduction in the production of microbial metabolites such as acetate, butyrate, isobutyrate, and some amino acids (alanine, serine, and hypoxanthine) observed in ME/CFS patients.

The lack of comparison under similar conditions with various standardized analytical methods has impeded the optimal calculation of results in ME/CFS patients and healthy controls. This review provides a comprehensive overview of the recent advancements in understanding the role of the gut microbiome in ME/CFS patients. Additionally, we have also discussed the potentials of using microbiome-related interventions and associated challenges to alleviate ME/CFS.

Source: Wang JH, Choi Y, Lee JS, Hwang SJ, Gu J, Son CG. Clinical evidence of the link between gut microbiome and myalgic encephalomyelitis/chronic fatigue syndrome: a retrospective review. Eur J Med Res. 2024 Mar 1;29(1):148. doi: 10.1186/s40001-024-01747-1. PMID: 38429822. https://eurjmedres.biomedcentral.com/articles/10.1186/s40001-024-01747-1 (Full text)

Graded exercise therapy compared to activity management for paediatric chronic fatigue syndrome/myalgic encephalomyelitis: pragmatic randomized controlled trial

Abstract

The MAGENTA pragmatic parallel groups randomized controlled trial compared graded exercise therapy (GET) with activity management (AM) in treating paediatric myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS). Children aged 8-17 years with mild/moderate ME/CFS and presenting to NHS specialist paediatric services were allocated at random to either individualised flexible treatment focussing on physical activity (GET, 123 participants) or on managing cognitive, school and social activity (AM, 118 participants) delivered by NHS therapists.

The primary outcome was the self-reported short-form 36 physical function subscale (SF-36-PFS) after 6 months, with higher scores indicating better functioning. After 6 months, data were available for 201 (83%) participants who received a mean of 3.9 (GET) or 4.6 (AM) treatment sessions. Comparing participants with measured outcomes in their allocated groups, the mean SF-36-PFS score changed from 54.8 (standard deviation 23.7) to 55.7 (23.3) for GET and from 55.5 (23.1) to 57.7 (26.0) for AM giving an adjusted difference in means of -2.02 (95% confidence interval -7.75, 2.70). One hundred thirty-five participants completed the mean SF-36-PFS at 12 months, and whilst further improvement was observed, the difference between the study groups remained consistent with chance.

The two study groups showed similar changes on most of the secondary outcome measures: Chalder Fatigue, Hospital Anxiety and Depression Scale: Depression, proportion of full-time school attended, a visual analogue pain scale, participant-rated change and accelerometer measured physical activity, whether at the 6-month or 12-month assessment.

There was an isolated finding of some evidence of an improvement in anxiety in those allocated to GET, as measured by the Hospital Anxiety and Depression Scale at 6 months, with the 12-month assessment, and the Spence Children’s Anxiety scale being aligned with that finding. There was weak evidence of a greater risk of deterioration with GET (27%) than with AM (17%; p = 0.069).

At conventional UK cost per QALY thresholds, the probability that GET is more cost-effective than AM ranged from 18 to 21%. Whilst completion of the SF-36-PFS, Chalder Fatigue Scale and EQ-5D-Y was good at the 6-month assessment point, it was less satisfactory for other measures, and for all measures at the 12-month assessment.

Conclusion: There was no evidence that GET was more effective or cost-effective than AM in this setting, with very limited improvement in either study group evident by the 6-month or 12-month assessment points.

Trial registration: The study protocol was registered at www.isrctn.com (3rd September 2015; ISRCTN 23962803) before the start of enrolment to the initial feasibility phase.

Source: Gaunt DM, Brigden A, Harris SRS, Hollingworth W, Jago R, Solomon-Moore E, Beasant L, Mills N, Sinai P, Crawley E, Metcalfe C. Graded exercise therapy compared to activity management for paediatric chronic fatigue syndrome/myalgic encephalomyelitis: pragmatic randomized controlled trial. Eur J Pediatr. 2024 Mar 2. doi: 10.1007/s00431-024-05458-x. Epub ahead of print. PMID: 38429546. https://link.springer.com/article/10.1007/s00431-024-05458-x (Full text)

The effect of comorbid medical diagnoses on disturbed sleep in chronic fatigue syndrome

Abstract:

Background: Chronic fatigue syndrome [CFS] may occur alone or with fibromyalgia. This has led some to believe the two occur along a common illness spectrum. Evaluating whether this is the case is important as differences in burden or severity of CFS with fibromyalgia (FM) would suggest different underlying pathophysiological processes.

Objective: To determine if Insomnia Severity Index [ISI] scores differ between patients with CFS and those with CFS plus FM. In addition, we aim to determine if insomnia severity is impacted by other comorbid medically unexplained diagnoses.

Methods: 247 patients with CFS completed the ISI and the Centers for Epidemiological Study – Depression. Patient groups were stratified on CFS severity and the presence of FM. A secondary analysis was conducted to evaluate insomnia severity related to the number of comorbid medically unexplained diagnoses including, FM, multiple chemical sensitivity and/or irritable bowel syndrome.

Results: When controlling for depressed mood, ISI did not differ significantly across patient groups defined by CFS severity and FM status. However, independent of mood, ISI was sensitive to multiple diagnoses showing a significant increasing trend from CFS alone to CFS plus one, two or three comorbid diagnoses.

Conclusion: Although CFS severity and FM status do not impact insomnia severity, increased illness burden as manifested by multiple medically unexplained diagnoses does appear to influence insomnia. In contrast to our earlier studies, this study did not find that a comorbid diagnosis of FM in patients with CFS is related to a worse outcome in the variable of interest.

Source: Aaron J. Stegner, Michelle Blate & Benjamin H. Natelson (2024) The effect of comorbid medical diagnoses on disturbed sleep in chronic fatigue syndrome, Fatigue: Biomedicine, Health & Behavior, DOI: 10.1080/21641846.2024.2322915 https://www.tandfonline.com/doi/full/10.1080/21641846.2024.2322915

Data and specimen-sharing tools offer new discovery opportunities for ME/CFS researchers

Summary: Within the field of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) research, two online tools: mapMECFS (Mathur and Carnes, 2021) and searchMECFS play a crucial role in advancing the understanding of ME/CFS by encouraging researchers to share and use data and biospecimens that are stored in centralized and easily accessible data portals

Overview: mapMECFS and searchMECFS are hosted by RTI International and funded by the National Institutes of Health (NIH). mapMECFS is the largest interactive portal and repository for ME/CFS data. It offers researchers from diverse disciplines a platform to share and integrate data from their ME/CFS research studies. searchMECFS is an interactive search tool that allows researchers to identify and request available biospecimens to conduct novel experiments.

Purpose and significance: mapMECFS aims to overcome the challenge of fragmented data sources in ME/CFS research by providing access to research results across many scientific disciplines and body systems. mapMECFS offers new opportunities for researchers by providing a centralized repository and tools to connect databases and enable exploration of complex study results. mapMECFS also serves as the repository for all experimental data generated from the use of biospecimens accessed through searchMECFS.

searchMECFS addresses the logistical challenge of biospecimen selection and access by assisting with the selection of biospecimens based on demographic and clinical attributes. Currently, searchMECFS houses demographic and clinical data from the Chronic Fatigue Initiative study and information about associated biospecimens stored in a central biorepository. Future plans include adding biospecimens from the Center for Disease Control and Prevention’s Multi-Site Clinical Assessment of ME/CFS study.

User registration and access: mapMECFS user registration is open to any researcher planning to use the data for research purposes. The secure registration process involves agreeing to the Data Use Agreement (DUA) and submitting a registration form that is reviewed by Program staff at NIH. Approved new users will either be added to an existing mapMECFS Organization or to a user-specific Organization created for them. Researchers approved to upload data will also be asked to complete a User Agreement.

To ensure secure data access, mapMECFS incorporates a two-tiered dataset structure. Private datasets, characterized by restricted visibility, are only accessible to users within the same Organization. Private datasets allow researchers to upload and prepare their data while they await the publication of the supporting manuscript. In contrast, public datasets are accessible to all approved users, fostering a collaborative and inclusive environment for research exploration.

Once a dataset’s supporting manuscript has been published, users are highly encouraged to make their results publicly available to registered users.

The registration process for searchMECFS mirrors that of mapMECFS, requiring similar information. Following approval, users can query the available biospecimens and associated demographic and clinical data. Once users identify their desired samples, they follow the link to the Biospecimen Resource Access Committee Application webpage where they find instructions and links to request the biospecimens of interest.

Data types and formats: mapMECFS supports a wide array of data types including proteomics, metabolomics, methylation, gene expression, microbiome, demographic, and health and survey data. The platform also accommodates supporting phenotype (clinical and demographic data) and data dictionaries. Data must be deidentified, so that all participant information is protected.

While formatting requirements vary for each data type, detailed documentation on the website guides researchers through the submission process, ensuring data consistency and integrity. The mapMECFS support team is also available to assist researchers with their data submissions.

Search and discovery: mapMECFS offers several features designed to assist researchers in accessing relevant data. These include (1) a user-friendly data explorer tool that enables researchers to effortlessly search for datasets containing specific analytes of interest and (2) a data integration tool which allows researchers to seamlessly merge clinical data files from specific cohorts.

searchMECFS provides an interactive query tool that can be used to build and execute data queries to find available biospecimens that meet the user’s specified search criteria. Users can add multiple search criteria to further enhance their search and refine their results.

Privacy and data standards: Participant privacy, a main priority, is covered within the DUAs and User Agreements. All data uploaded on mapMECFS must be free of Personally Identifiable Information (PII). Agreements also cover responsible data use including refraining from attempting to identify participants, safeguards against unintentional disclosure, prompt reporting of any unauthorized use, and restrictions on using the data for clinical or medical purposes. It is the uploader’s responsibility to ensure that PII is not present, participant privacy is fully protected, and sharing is compliant with all other governing policies (e.g., IRB-approved protocols, embargos).

Future directions and user engagement: The development of mapMECFS is guided by user input, prioritizing site enhancements according to the feedback received from researchers actively engaging with the platform. All site users are encouraged to contact the mapMECFS support team with suggestions to improve the site. RTI plans to expand the clinical and biological data within the site’s integration tool and improve data standards and automated quality assurance pipelines. RTI is also working with the ME/CFS research community to expand the number of datasets publicly available in mapMECFS and to increase the number of biospecimens available through searchMECFS.

Funders: US National Institutes of Health (NIH): National Institute of Neurological Disorders and Stroke (NINDS); National Institute of Allergy and Infectious Diseases (NIAID); National Heart, Lung, and Blood Institute (NHLBI); National Center for Complementary and Integrative Health (NCCIH); and National Institute on Alcohol Abuse and Alcoholism (NIAAA)

Acknowledgement: This work was supported by the National Institutes of Health (NIH) under award number U24NS105535. The contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIH or RTI International.

Source: RTI International, USA

Heterogeneity in Measures of Illness among Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Is Not Explained by Clinical Practice: A Study in Seven U.S. Specialty Clinics

Abstract:

Background: One of the goals of the Multi-site Clinical Assessment of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (MCAM) study was to evaluate whether clinicians experienced in diagnosing and caring for patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) recognized the same clinical entity.
Methods: We enrolled participants from seven specialty clinics in the United States. We used baseline data (n = 465) on standardized questions measuring general clinical characteristics, functional impairment, post-exertional malaise, fatigue, sleep, neurocognitive/autonomic symptoms, pain, and other symptoms to evaluate whether patient characteristics differed by clinic.
Results: We found few statistically significant and no clinically significant differences between clinics in their patients’ standardized measures of ME/CFS symptoms and function. Strikingly, patients in each clinic sample and overall showed a wide distribution in all scores and measures.
Conclusions: Illness heterogeneity may be an inherent feature of ME/CFS. Presenting research data in scatter plots or histograms will help clarify the challenge. Relying on case–control study designs without subgrouping or stratification of ME/CFS illness characteristics may limit the reproducibility of research findings and could obscure underlying mechanisms.
Source: Unger ER, Lin J-MS, Chen Y, Cornelius ME, Helton B, Issa AN, Bertolli J, Klimas NG, Balbin EG, Bateman L, et al. Heterogeneity in Measures of Illness among Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Is Not Explained by Clinical Practice: A Study in Seven U.S. Specialty Clinics. Journal of Clinical Medicine. 2024; 13(5):1369. https://doi.org/10.3390/jcm13051369 https://www.mdpi.com/2077-0383/13/5/1369 (Full text)

Spontaneous, persistent, T cell-dependent IFN-γ release in patients who progress to Long Covid

Abstract:

After acute infection with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), a proportion of patients experience persistent symptoms beyond 12 weeks, termed Long Covid. Understanding the mechanisms that cause this debilitating disease and identifying biomarkers for diagnostic, therapeutic, and monitoring purposes are urgently required.

We detected persistently high levels of interferon-γ (IFN-γ) from peripheral blood mononuclear cells of patients with Long Covid using highly sensitive FluoroSpot assays. This IFN-γ release was seen in the absence of ex vivo peptide stimulation and remains persistently elevated in patients with Long Covid, unlike the resolution seen in patients recovering from acute SARS-CoV-2 infection. The IFN-γ release was CD8+ T cell-mediated and dependent on antigen presentation by CD14+ cells.

Longitudinal follow-up of our study cohort showed that symptom improvement and resolution correlated with a decrease in IFN-γ production to baseline levels. Our study highlights a potential mechanism underlying Long Covid, enabling the search for biomarkers and therapeutics in patients with Long Covid.

Source: Krishna BA, Lim EY, Metaxaki M, Jackson S, Mactavous L; NIHR BioResource; Lyons PA, Doffinger R, Bradley JR, Smith KGC, Sinclair J, Matheson NJ, Lehner PJ, Sithole N, Wills MR. Spontaneous, persistent, T cell-dependent IFN-γ release in patients who progress to Long Covid. Sci Adv. 2024 Feb 23;10(8):eadi9379. doi: 10.1126/sciadv.adi9379. Epub 2024 Feb 21. PMID: 38381822; PMCID: PMC10881041. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10881041/ (Full text)