Respiratory SARS-CoV-2 Infection Causes Skeletal Muscle Atrophy and Long-Lasting Energy Metabolism Suppression

Abstract:

Muscle fatigue represents the most prevalent symptom of long-term COVID, with elusive pathogenic mechanisms. We performed a longitudinal study to characterize histopathological and transcriptional changes in skeletal muscle in a hamster model of respiratory SARS-CoV-2 infection and compared them with influenza A virus (IAV) and mock infections.

Histopathological and bulk RNA sequencing analyses of leg muscles derived from infected animals at days 3, 30, and 60 post-infection showed no direct viral invasion but myofiber atrophy in the SARS-CoV-2 group, which was accompanied by persistent downregulation of the genes related to myofibers, ribosomal proteins, fatty acid β-oxidation, tricarboxylic acid cycle, and mitochondrial oxidative phosphorylation complexes.

While both SARS-CoV-2 and IAV infections induced acute and transient type I and II interferon responses in muscle, only the SARS-CoV-2 infection upregulated TNF-α/NF-κB but not IL-6 signaling in muscle. Treatment of C2C12 myotubes, a skeletal muscle cell line, with combined IFN-γ and TNF-α but not with IFN-γ or TNF-α alone markedly impaired mitochondrial function.

We conclude that a respiratory SARS-CoV-2 infection can cause myofiber atrophy and persistent energy metabolism suppression without direct viral invasion. The effects may be induced by the combined systemic interferon and TNF-α responses at the acute phase and may contribute to post-COVID-19 persistent muscle fatigue.

Source: Homma ST, Wang X, Frere JJ, Gower AC, Zhou J, Lim JK, tenOever BR, Zhou L. Respiratory SARS-CoV-2 Infection Causes Skeletal Muscle Atrophy and Long-Lasting Energy Metabolism Suppression. Biomedicines. 2024 Jun 28;12(7):1443. doi: 10.3390/biomedicines12071443. PMID: 39062017; PMCID: PMC11275164. https://pmc.ncbi.nlm.nih.gov/articles/PMC11275164/ (Full text)

Persistent Fatigue, Weakness, and Aberrant Muscle Mitochondria in Survivors of Critical COVID-19

Abstract:

Objectives: Persistent skeletal muscle dysfunction in survivors of critical illness due to acute respiratory failure is common, but biological data elucidating underlying mechanisms are limited. The objective of this study was to elucidate the prevalence of skeletal muscle weakness and fatigue in survivors of critical illness due to COVID-19 and determine if cellular changes associate with persistent skeletal muscle dysfunction.

Design: A prospective observational study in two phases: 1) survivors of critical COVID-19 participating in physical outcome measures while attending an ICU Recovery Clinic at short-term follow-up and 2) a nested cohort of patients performed comprehensive muscle and physical function assessments with a muscle biopsy; data were compared with non-COVID controls.

Setting: ICU Recovery Clinic and clinical laboratory.

Patients/subjects: Survivors of critical COVID-19 and non-COVID controls.

Interventions: None.

Measurements and main results: One hundred twenty patients with a median of 56 years old (interquartile range [IQR], 42-65 yr old), 43% female, and 33% individuals of underrepresented race attended follow-up 44 ± 17 days after discharge. Patients had a median Acute Physiology and Chronic Health Evaluation-II score of 24.0 (IQR, 16-29) and 98 patients (82%) required mechanical ventilation with a median duration of 14 days (IQR, 9-21 d). At short-term follow-up significant physical dysfunction was observed with 93% of patients reporting generalized fatigue and performing mean 218 ± 151 meters on 6-minute walk test (45% ± 30% of predicted). Eleven patients from this group agreed to participate in long-term assessment and muscle biopsy occurring a mean 267 ± 98 days after discharge. Muscle tissue from COVID exhibited a greater abundance of M2-like macrophages and satellite cells and lower activity of mitochondrial complex II and complex IV compared with controls.

Conclusions: Our findings suggest that aberrant repair and altered mitochondrial activity in skeletal muscle associates with long-term impairments in patients surviving an ICU admission for COVID-19.

Source: Mayer KP, Ismaeel A, Kalema AG, Montgomery-Yates AA, Soper MK, Kern PA, Starck JD, Slone SA, Morris PE, Dupont-Versteegden EE, Kosmac K. Persistent Fatigue, Weakness, and Aberrant Muscle Mitochondria in Survivors of Critical COVID-19. Crit Care Explor. 2024 Oct 16;6(10):e1164. doi: 10.1097/CCE.0000000000001164. PMID: 39412208; PMCID: PMC11487221. https://pmc.ncbi.nlm.nih.gov/articles/PMC11487221/ (Full text)

Catalytic Antibodies May Contribute to Demyelination in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

Here we report preliminary data demonstrating that some patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) may have catalytic autoantibodies that cause the breakdown of myelin basic protein (MBP). We propose that these MBP-degradative antibodies are important to the pathophysiology of ME/CFS, particularly in the occurrence of white matter disease/demyelination. This is supported by magnetic resonance imagining studies that show these findings in patients with ME/CFS and could explain symptoms of nerve pain and muscle weakness.

In this work, we performed a series of experiments on patient plasma samples where we isolated and characterized substrate-specific antibodies that digest MBP. We also tested glatiramer acetate (copaxone), an FDA approved immunomodulator to treat multiple sclerosis, and found that it inhibits ME/CFS antibody digestion of MBP. Furthermore, we found that aprotinin, which is a specific serine protease inhibitor, specifically prevents breakdown of MBP while the other classes of protease inhibitors had no effect. This coincides with the published literature describing catalytic antibodies as having serine protease-like activity. Postpandemic research has also provided several reports of demyelination in COVID-19.

Because COVID-19 has been described as a trigger for ME/CFS, demyelination could play a bigger role in patient symptoms for those recently diagnosed with ME/CFS. Therefore, by studying proteolytic antibodies in ME/CFS, their target substrates, and inhibitors, a new mechanism of action could lead to better treatment and a possible cure for the disease.

Source: Jensen MA, Dafoe ML, Wilhelmy J, Cervantes L, Okumu AN, Kipp L, Nemat-Gorgani M, Davis RW. Catalytic Antibodies May Contribute to Demyelination in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Biochemistry. 2023 Nov 27. doi: 10.1021/acs.biochem.3c00433. Epub ahead of print. PMID: 38011893. https://pubs.acs.org/doi/10.1021/acs.biochem.3c00433 (Full text)

A prospective randomized, double-blind placebo-controlled study to evaluate the effectiveness of neuroprotective therapy using functional brain MRI in patients with post-covid chronic fatigue syndrome

Abstract:

Background and purpose: to assess executive network using resting-state fMRI and patterns of brain activation using task fMRI with a cognitive paradigm, against the background of taking the drug in comparison with placebo in patients with post-COVID asthenic syndrome.

Methods: The study employed a prospective, randomized, double-blind, placebo-controlled trial approach to assess the efficacy of utilizing functional MRI of the brain as a neuroprotective therapy for treating patients with chronic fatigue syndrome following COVID-19. The study included 30 patients matched by sex and age with post-COVID asthenic syndrome. All patients were examined with MFI-20, MoCA, FAS-10 scales, MRI using a Siemens MAGNETOM Prisma 3 T scanner before and after a course of therapy with coordination complex with succinate acid anion (CCSA) or placebo (15 patients each) using resting state fMRI and with cognitive paradigm.

Results: The changes obtained as a result of the treatment of post-Covid asthenic syndrome demonstrated clinical superiority in the reduction of asthenic symptoms for the group of patients treated with CCSA (MFI-20 scores: -20·0 points in the CCSA group compared to -12 points in the placebo group, p = 0·043). The data obtained also correlate with the analysis of task fMRI and resting state fMRI may indicate an increase in the functional cognitive status after a course of therapy with CCSA. Clinically, this correlates with a statistically significant improvement in the MoCA score (2 points in the CCSA group compared to 1 point in the placebo group, p < 0·05).

Conclusions: The study demonstrates the potential effectiveness of CCSA therapy in relation to a wide range of symptoms (chronic fatigue syndrome/ asthenic syndrome and cognitive impairment) in patients with post-COVID syndrome. The first time demonstrated the effectiveness of neuroprotective therapy after post-COVID asthenic syndrome with the use of high-tech neuroimaging techniques.

Source: Tanashyan M, Morozova S, Raskurazhev A, Kuznetsova P. A prospective randomized, double-blind placebo-controlled study to evaluate the effectiveness of neuroprotective therapy using functional brain MRI in patients with post-covid chronic fatigue syndrome. Biomed Pharmacother. 2023 Oct 18;168:115723. doi: 10.1016/j.biopha.2023.115723. Epub ahead of print. PMID: 37862966. https://www.sciencedirect.com/science/article/pii/S0753332223015214 (Full study)

People with Long Covid and ME/CFS Exhibit Similarly Impaired Balance and Physical Capacity: A Case-Case-Control Study

Abstract:

Purpose: Postural sway and physical capacity had not previously been compared between people with long COVID and people with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). Therefore, this study determined postural sway and physical capacity in people with long COVID (∼16 month illness duration; n=21) and ME/CFS (∼16 year illness duration; n=20), versus age-matched healthy controls (n=20).

Methods: Postural sway was during a 30 s static stand test. Physical capacity was determined using the timed up and go test and five times sit to stand test. Throughout, participants wore isoinertial measurement units.

Results: Postural sway was worse (i.e. greater) in people with long COVID and ME/CFS than controls, but not different between long COVID and ME/CFS. Performance of the timed up and go test and five times sit to stand test were worse in long COVID and ME/CFS than controls, but not different between long COVID and ME/CFS. 87% and 13% of long COVID and ME/CFS participants exceeded the threshold for muscle weakness in the five times sit to stand test and timed up and go test, respectively.

Conclusions: These data suggest that both people with long COVID and people with ME/CFS have similarly impaired balance and physical capacity. Therefore, there is an urgent need for interventions to target postural sway and physical capacity in people with ME/CFS, and given the current pandemic, people with long COVID.

Source: Lawrence D. Hayes, PhD, Nilihan E.M. Sanal-Hayes, PhD, Marie Mclaughlin, PhD, Ethan C.J. Berry, BSc (Hons), Nicholas F. Sculthorpe, PhD. People with Long Covid and ME/CFS Exhibit Similarly Impaired Balance and Physical Capacity: A Case-Case-Control Study. The American Journal of Medicine. Published: July 23, 2023 DOI: https://doi.org/10.1016/j.amjmed.2023.06.028 https://www.amjmed.com/article/S0002-9343(23)00465-5/fulltext#%20

Sonographic Diaphragm Abnormalities are an Unexpectedly Frequent Feature of Long COVID Outpatients with Unexplained Dyspnea and Fatigue

Abstract:

Purpose: The primary aim of this study is to define the sonographic diaphragm phenotype of Long COVID rehabilitation outpatients with non-specific dyspnea and fatigue. We analyzed patients referred from a pulmonary post-COVID clinic that were lacking a specific cardiopulmonary diagnosis for their symptoms. Additionally, we report the functional outcomes of subset of patients who completed an outpatient cardiopulmonary physical therapy program.

Methods: This was a retrospective cohort study (n = 58) of consecutive patients referred for neuromuscular ultrasound assessment of diaphragm muscle using B-mode technique. Patients were recruited from a single academic hospital between February 25, 2021 and November 22, 2022.

Results: Sonographic abnormalities were identified in 57% (33/58) of patients, and in the vast majority of cases (33/33) was defined by a low diaphragm muscle thickness. Thinner diaphragm muscles are correlated with lower serum creatinine and creatine kinase values, but there was no association with markers of systemic inflammation. Thirty three patients participated in outpatient cardiopulmonary physical therapy that included respiratory muscle training, and 75.8% (25/33) had documented improvement.

Conclusion: In the outpatient rehabilitation setting, patients with Long COVID display low diaphragm muscle thickness, but intact muscle contractility, with surprising frequency on neuromuscular ultrasound. We speculate this represents a form of disuse atrophy. Also, these patients appear to have a favorable response to cardiopulmonary physical therapy that includes respiratory muscle training.

Source: Prabhav P. DeoJoseph I. BaileyAlexandra S. JensenEllen FarrMeghan FaheyMatthew IsherwoodKeerthana ChakkaLisa F. WolfeIshan RoyMarc A. SalaColin K. Franz. Sonographic Diaphragm Abnormalities are an Unexpectedly Frequent Feature of Long COVID Outpatients with Unexplained Dyspnea and Fatigue. (Full text)

Sarcopenia as potential biological substrate of long COVID-19 syndrome: prevalence, clinical features, and risk factors

Abstract:

Background: Severe clinical pictures and sequelae of COVID-19 disease are immune mediated and characterized by a ‘cytokine storm’. Skeletal muscle has emerged as a potent regulator of immune system function. The aim of the present study is to define the prevalence of sarcopenia among COVID-19 survivors and the negative impact of sarcopenia on the post-acute COVID-19 syndrome and its related risk factors.

Methods: A total of 541 subjects recovered from COVID-19 disease were enrolled in the Gemelli Against COVID-19 Post-Acute Care between April 2020 and February 2021. They underwent a multidisciplinary clinical evaluation and muscle strength and physical performance assessment.

Results: Mean age was 53.1 years (SD 15.2, range from 18 to 86 years), and 274 (51%) were women. The prevalence of sarcopenia was 19.5%, and it was higher in patients with a longer hospital stay and lower in patients who were more physically active and had higher levels of serum albumin. Patients with sarcopenia had a higher number of persistent symptoms than non-sarcopenic patients (3.8 ± 2.9 vs. 3.2 ± 2.8, respectively; P = 0.06), in particular fatigue, dyspnoea, and joint pain.

Conclusions: Sarcopenia identified according to the EWGSOP2 criteria is high in patients recovered from COVID-19 acute illness, particularly in those who had experienced the worst clinical picture reporting the persistence of fatigue and dyspnoea. Our data suggest that sarcopenia, through the persistence of inflammation, could be the biological substrate of long COVID-19 syndrome. Physical activity, especially if associated with adequate nutrition, seems to be an important protective factor.

Source: Martone AM, Tosato M, Ciciarello F, Galluzzo V, Zazzara MB, Pais C, Savera G, Calvani R, Marzetti E, Robles MC, Ramirez M, Landi F; Gemelli Against COVID-19 Post-Acute Care Team. Sarcopenia as potential biological substrate of long COVID-19 syndrome: prevalence, clinical features, and risk factors. J Cachexia Sarcopenia Muscle. 2022 Jun 14. doi: 10.1002/jcsm.12931. Epub ahead of print. PMID: 35698920. https://onlinelibrary.wiley.com/doi/10.1002/jcsm.12931 (Full text)

Myopathy as a cause of fatigue in long-term post-COVID-19 symptoms: Evidence of skeletal muscle histopathology

Abstract:

Background: Among post-COVID-19 symptoms, fatigue is reported as one of the most common, even after mild acute infection, and as the cause of fatigue, myopathy diagnosed by electromyography has been proposed in previous reports. This study aimed to explore the histopathological changes in patients with post-COVID-19 fatigue.

Methods: Sixteen patients (mean age:46 years) with post-COVID-19 complaints of fatigue, myalgia or weakness persisting for up to 14 months were included. In all patients, quantitative electromyography and muscle biopsies analysed with light and electron microscopy were taken.

Results: Muscle weakness was present in 50%, myopathic electromyography in 75% while in all patients, there were histological changes. Muscle fiber atrophy was found in 38%, and 56% showed indications of fiber regeneration. Mitochondrial changes, comprising loss of COX activity, subsarcollemmal accumulation and/or abnormal cristae, were present in 62%. Inflammation was found in 62%, seen as T-lymphocytes and/or muscle fiber HLA-ABC expression. In 75%, capillaries were affected involving basal lamina and cells. In two patients, uncommon amounts of basal lamina were found, not only surrounding muscle fibers but also around nerves and capillaries.

Conclusions: The wide variety of histological changes in this study suggest that skeletal muscles may be a major target of SARS-CoV-2 causing muscular post-COVID-19 symptoms. The mitochondrial changes, inflammation and capillary injury in muscle biopsies can cause fatigue in part due to reduced energy supply. Since most patients had mild-moderate acute affection, the new variants that might cause less severe acute disease could still have the ability to cause long-term myopathy.

Source: Hejbøl EK, Harbo T, Agergaard J, Madsen LB, Pedersen TH, Østergaard LJ, Andersen H, Schrøder HD, Tankisi H. Myopathy as a cause of fatigue in long-term post-COVID-19 symptoms: Evidence of skeletal muscle histopathology. Eur J Neurol. 2022 Jun 6. doi: 10.1111/ene.15435. Epub ahead of print. PMID: 35661354.  https://pubmed.ncbi.nlm.nih.gov/35661354/ https://pubmed.ncbi.nlm.nih.gov/35661354/ (Full text available as PDF file)

Skeletal muscle alterations in patients with acute Covid-19 and post-acute sequelae of Covid-19

Abstract:

Background and methods: Skeletal muscle-related symptoms are common in both acute Covid-19 and Post-Acute Sequelae of Covid-19 (PASC). In this narrative review, we discuss cellular and molecular pathways that are affected, and consider these in regard to skeletal muscle involvement in other conditions, such as acute respiratory distress syndrome, critical illness myopathy and post-viral fatigue syndrome.
Results: Patients with severe Covid-19 and PASC suffer from skeletal muscle weakness and exercise intolerance. Histological sections present muscle fiber atrophy, metabolic alterations, and immune cell infiltration. Contributing factors to weakness and fatigue in patients with severe Covid-19 include systemic inflammation, disuse, hypoxemia, and malnutrition. These factors also contribute to post-ICU syndrome and ICU-acquired weakness, and likely explain a substantial part of Covid-19-acquired weakness. The skeletal muscle weakness and exercise intolerance associated with PASC are more obscure and different factors likely contribute. Direct SARS-CoV-2 viral infiltration into skeletal muscle or an aberrant immune system likely contribute. Similarities between skeletal muscle alterations in PASC and chronic fatigue syndrome deserve further study.
Conclusion: Both SARS-CoV-2 specific factors and generic consequences of acute disease likely underlie the observed skeletal muscle alterations in both acute Covid 19 and PASC.
Source: Soares, M., Eggelbusch, M., Naddaf, E., Gerrits, K., van der Schaaf, M., van den Borst, B., Wiersinga, W. J., et al. Skeletal muscle alterations in patients with acute Covid-19 and post-acute sequelae of Covid-19. Journal of Cachexia, Sarcopenia and Muscle. https://doi.org/10.17863/CAM.78509 https://www.repository.cam.ac.uk/handle/1810/331064

Timed loaded standing in female chronic fatigue syndrome compared with other populations

Erratum in

  • J Rehabil Res Dev. 2015;52(7):859.

Abstract:

Patients with chronic fatigue syndrome (CFS), like patients with osteoporosis, have similar difficulties in standing and sitting. The aim of the study was to compare combined trunk and arm endurance among women with CFS (n = 72), women with osteoporosis (n = 30), nondisabled women (n = 55), and women from non-industrialized countries (n = 58) using the timed loaded standing (TLS) test. TLS measures how long a person can hold a 1 kg dumbbell in each hand in front of him or her with straight arms. TLS was higher in the industrialized nondisabled population than in the non-industrialized study population (p < 0.001) and in patients with osteoporosis (p = 0.002).

TLS was lower in patients with CFS than in nondisabled controls (p < 0.001). After adjusting for age, body height, and weight, combined trunk and arm endurance was lower in CFS patients than in osteoporotic patients, even though the patients with osteoporosis were more than 25 yr older (p < 0.001) [corrected]. In CFS, TLS was lower than in the non-industrialized group (p = 0.02). Since only women were studied, external validity of the results is limited to adult female patients with CFS. TLS revealed a specific biomechanical weakness in CFS patients that can be taken into account from the onset of a rehabilitation program. We propose that influencing the quality, rather than the quantity, of movement could be used in the rehabilitation.

 

Source: Eyskens JB, Nijs J, D’Août K, Sand A, Wouters K, Moorkens G. Timed loaded standing in female chronic fatigue syndrome compared with other populations. J Rehabil Res Dev. 2015;52(1):21-9. doi: 10.1682/JRRD.2014.03.0086. http://www.rehab.research.va.gov/jour/2015/521/JRRD-2014-03-0086.html (Full article)