Cardiopulmonary and metabolic responses during a 2-day CPET in myalgic encephalomyelitis/chronic fatigue syndrome: translating reduced oxygen consumption to impairment status to treatment considerations

Abstract:

Background: Post-exertional malaise (PEM), the hallmark symptom of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), represents a constellation of abnormal responses to physical, cognitive, and/or emotional exertion including profound fatigue, cognitive dysfunction, and exertion intolerance, among numerous other maladies. Two sequential cardiopulmonary exercise tests (2-d CPET) provide objective evidence of abnormal responses to exertion in ME/CFS but validated only in studies with small sample sizes. Further, translation of results to impairment status and approaches to symptom reduction are lacking.

Methods: Participants with ME/CFS (Canadian Criteria; n = 84) and sedentary controls (CTL; n = 71) completed two CPETs on a cycle ergometer separated by 24 h. Two-way repeated measures ANOVA compared CPET measures at rest, ventilatory/anaerobic threshold (VAT), and peak effort between phenotypes and CPETs. Intraclass correlations described stability of CPET measures across tests, and relevant objective CPET data indicated impairment status. A subset of case–control pairs (n = 55) matched for aerobic capacity, age, and sex, were also analyzed.

Results: Unlike CTL, ME/CFS failed to reproduce CPET-1 measures during CPET-2 with significant declines at peak exertion in work, exercise time, V˙e, V˙O2, V˙CO2, V˙ T, HR, O2pulse, DBP, and RPP. Likewise, CPET-2 declines were observed at VAT for V˙e/V˙CO2, PetCO2, O2pulse, work, V˙O2 and SBP. Perception of effort (RPE) exceeded maximum effort criteria for ME/CFS and CTL on both CPETs. Results were similar in matched pairs. Intraclass correlations revealed greater stability in CPET variables across test days in CTL compared to ME/CFS owing to CPET-2 declines in ME/CFS. Lastly, CPET-2 data signaled more severe impairment status for ME/CFS compared to CPET-1.

Conclusions: Presently, this is the largest 2-d CPET study of ME/CFS to substantiate impaired recovery in ME/CFS following an exertional stressor. Abnormal post-exertional CPET responses persisted compared to CTL matched for aerobic capacity, indicating that fitness level does not predispose to exertion intolerance in ME/CFS. Moreover, contributions to exertion intolerance in ME/CFS by disrupted cardiac, pulmonary, and metabolic factors implicates autonomic nervous system dysregulation of blood flow and oxygen delivery for energy metabolism. The observable declines in post-exertional energy metabolism translate notably to a worsening of impairment status. Treatment considerations to address tangible reductions in physiological function are proffered.

Trial registration number: ClinicalTrials.gov, retrospectively registered, ID# NCT04026425, date of registration: 2019-07-17.

Source: Keller, B., Receno, C.N., Franconi, C.J. et al. Cardiopulmonary and metabolic responses during a 2-day CPET in myalgic encephalomyelitis/chronic fatigue syndrome: translating reduced oxygen consumption to impairment status to treatment considerations. J Transl Med 22, 627 (2024). https://doi.org/10.1186/s12967-024-05410-5 https://translational-medicine.biomedcentral.com/articles/10.1186/s12967-024-05410-5#Abs1 (Full text)

 

Novel characterization of endogenous transient receptor potential melastatin 3 ion channels from Gulf War Illness participants

Abstract:

Gulf War Illness (GWI) is a chronic condition characterized by multisystem symptoms that still affect up to one-third of veterans who engaged in combat in the Gulf War three decades ago. The aetiology of GWI is mainly explained by exposure to multiple toxic agents, vaccines, and medications. As there is a significant overlap in symptoms between GWI and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), the objective of this study was to investigate a biomarker widely reported in Natural Killer (NK) cells from ME/CFS patients, the Transient Receptor Potential Melastatin 3 (TRPM3) ion channel.

NK cells from 6 healthy controls (HC) and 6 GWI participants were isolated, and TRPM3 function was assessed through whole-cell patch-clamp. As demonstrated by prior studies, NK cells from HC expressed typical TRPM3 function after pharmacomodulation.

In contrast, this pilot investigation demonstrates a dysfunctional TRPM3 in NK cells from GWI participants through application of a TRPM3 agonist and confirmed by a TRPM3 antagonist. There was a significant reduction in TRPM3 function from GWI than results measured in HC. This study provides an unprecedented research field to investigate the involvement of TRP ion channels in the pathomechanism and potential medical interventions to improve GWI quality of life.

Source: Marshall-Gradisnik S, Martini Sasso E, Eaton-Fitch N, Smith P, Baraniuk JN, Muraki K. Novel characterization of endogenous transient receptor potential melastatin 3 ion channels from Gulf War Illness participants. PLoS One. 2024 Jun 25;19(6):e0305704. doi: 10.1371/journal.pone.0305704. PMID: 38917121; PMCID: PMC11198784. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11198784/ (Full text)

Flow Clotometry: Measuring Amyloid Microclots in ME/CFS, Long COVID, and Healthy Samples with Imaging Flow Cytometry

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) has received more attention since the characterization of Long COVID (LC), a condition somewhat similar in symptom presentation and, to some extent, pathophysiological mechanisms. A prominent feature of LC pathology is amyloid, fibrinolysis-resistant fibrin(ogen) fragments, termed microclots. Despite prior identification of microclots in ME/CFS, quantitative analysis has remained challenging due to the reliance on representative micrographs and software processing for estimations.

Addressing this gap, the present study uses a cell-free imaging flow cytometry approach, optimized for the quantitative analysis of Thioflavin T-stained microclots, to precisely measure microclot concentration and size distribution across ME/CFS, LC, and healthy cohorts. We refer to our cell-free flow cytometry technique for detecting microclots as ‘flow clotometry’.

We demonstrate significant microclot prevalence in ME/CFS and LC, with LC patients exhibiting the highest concentration (18- and 3-fold greater than the healthy and ME/CFS groups, respectively). This finding underscores a common pathology across both conditions, emphasizing a dysregulated coagulation system. Moreover, relating to microclot size distribution, the ME/CFS group exhibited a significantly higher prevalence across all area ranges when compared to the controls, but demonstrated a significant difference for only a single area range when compared to the LC group.

This suggests a partially overlapping microclot profile in ME/CFS relative to LC, despite the overall higher concentration in the latter. The present study paves the way for prospective clinical application that aims to efficiently detect, measure and treat microclots.

Source: Etheresia Pretorius, Massimo Nunes, Jan pretorius et al. Flow Clotometry: Measuring Amyloid Microclots in ME/CFS, Long COVID, and Healthy Samples with Imaging Flow Cytometry, 24 June 2024, PREPRINT (Version 1) available at Research Square [https://doi.org/10.21203/rs.3.rs-4507472/v1] https://www.researchsquare.com/article/rs-4507472/v1 (Full text)

Reduction of long COVID symptoms after stellate ganglion block: A retrospective chart review study

Abstract:

The SARS-CoV-2 pandemic has left millions of individuals with a host of post-viral symptoms that can be debilitating and persist indefinitely. To date there are no definitive tests or treatments for the collection of symptoms known as “Long COVID” or Post-acute sequelae of COVID-19 (PASC). Following our initial case report detailing improvement of Long COVID symptoms after sequential bilateral stellate ganglion blockade (SGB), we performed a retrospective chart analysis study on individuals treated with the same protocol over the course of six months (2021-2022) in our clinic.

Patients self-reported symptoms on a 10-point scale as part of optional patient follow-up using an online survey. After one month or more following treatment, patients reported striking reductions in Fatigue, Worsening of Symptoms following Mental and Physical Activity, Memory Problems, Problems Concentrating, Sleep Problems, Anxiety, and Depression. Loss of Taste and Loss of Smell in some individuals did not respond to treatment, likely indicating structural damage following infection.

This study suggests that neuromodulation may provide relief of Long COVID symptoms for at least a subset of individuals, and provides support for prospective studies of this potential treatment.

Source: Duricka D, Liu L. Reduction of long COVID symptoms after stellate ganglion block: A retrospective chart review study. Auton Neurosci. 2024 Jun 13;254:103195. doi: 10.1016/j.autneu.2024.103195. Epub ahead of print. PMID: 38901177. https://www.autonomicneuroscience.com/article/S1566-0702(24)00049-3/fulltext (Full text)

Successful Subcutaneous Immunoglobulin Therapy in a Case Series of Patients With Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

Purpose: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) remains an enigma with no curable treatment options at hand. Although patients with ME/CFS are a heterogeneous group, a large proportion of patients present with an infection-driven symptomatology, making them potential responders to immunologic treatments, such as immunoglobulin (IG). Previous studies on IG treatment in patients with ME/CFS have not been consistent but have described beneficial effects in subgroups of patients.

Methods: Here we present data on a series of cases (n = 17) with infection-related ME/CFS (as defined by disease history and ongoing recurrent infections) treated with subcutaneous low-dose IG (0.06 g/kg/mo) over 5 weeks with continuous monitoring of symptoms.

Findings: Patients were predominantly female (65%) with mild-to-moderate disease severity (82%) and with poor self-reported quality of life (median, 25 on a 0-100 scale) and working ability (median, 5 on a 0-100 scale) before treatment. After 5 weeks of treatment with low-dose IG, significant improvements in symptoms, quality of life, and working ability were noted (all P < 0.05). Among the 7 patients who reported the highest benefit of the treatment, quality of life increased by 35 units (on a 0-100 scale), with 1 patient reporting complete elimination of ME/CFS symptoms. No serious side effects were detected with the treatment.

Implications: In this limited-sized case series, we found pronounced beneficial effects of low-dose IG in a large proportion of patients with infection-related ME/CFS. Further well-controlled studies are needed to verify the potential benefits of IG treatment in patients with ME/CFS with infection-driven symptomatology.

Source: Sjogren P, Bragée B, Britton S. Successful Subcutaneous Immunoglobulin Therapy in a Case Series of Patients With Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Clin Ther. 2024 Jun 22:S0149-2918(24)00131-0. doi: 10.1016/j.clinthera.2024.05.010. Epub ahead of print. PMID: 38910072.

Assessing Functional Capacity in Myalgic Encephalopathy/Chronic Fatigue Syndrome: A Patient-Informed Questionnaire

Abstract:

Background: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is an acquired disease with significant morbidity that affects both children and adults. Post-exertional malaise is a cardinal symptom of ME/CFS and impacts a patient’s functional capacity (FC). The absence of effective tools to assess FC has significant consequences for timely diagnosis, clinical follow-up, assessments for patient disability benefits, and research studies. In interventional studies, the inability to assess FC can result in an incomplete assessment of the potential benefit of the intervention, leading to beneficial treatment outcomes being missed.
Methods: Using extensive, repeated patient feedback, we have developed a new questionnaire, FUNCAP, to accurately assess FC in ME/CFS patients. The questionnaire consists of eight domains divided by activity types: A. personal hygiene/basic functions, B. walking/movement, C. being upright, D. activities in the home, E. communication, F. activities outside the home, G. reactions to light and sound, and H. concentration.
Results: Through five rounds of anonymous web-based surveys and a further test–retest validation round, two versions of the questionnaire were developed: a longer version comprising 55 questions (FUNCAP55), developed for improved diagnostic and disability benefit/insurance FC assessments; and a shorter version (FUNCAP27) for clinical patient follow-up and potential use in research. Good reliability and validity and negligible floor and ceiling effects were found, with comparable findings in all aspects in both a large Norwegian (n = 1263) and a separate English-language international sample (n = 1387) demonstrating the validity and reliability of FUNCAP.
Conclusions: Our findings support the utility of FUNCAP as an effective, reliable and valid tool for assessing FC in ME/CFS patients.
Source: Sommerfelt K, Schei T, Seton KA, Carding SR. Assessing Functional Capacity in Myalgic Encephalopathy/Chronic Fatigue Syndrome: A Patient-Informed Questionnaire. Journal of Clinical Medicine. 2024; 13(12):3486. https://doi.org/10.3390/jcm13123486 https://www.mdpi.com/2077-0383/13/12/3486 (Full text)

Systems Modeling Reveals Shared Metabolic Dysregulation and Novel Therapeutic Treatments in ME/CFS and Long COVID

Abstract:

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Long COVID are complex, multisystemic conditions that pose ongoing challenges to healthcare professionals. Emerging research suggests that ME/CFS and Long COVID exhibit overlapping metabolic symptoms, indicating possible shared metabolic dysfunctions. This study aims to systematically explore these shared metabolic disturbances and their potential treatments.

Utilizing our novel metabolic modeling method, GPMM, we identified the key metabolic irregularities in patients with ME/CFS and Long COVID, notably the downregulation of the alanine and aspartate metabolism pathway, and the arginine and proline metabolism pathway.

Genome-wide knockout analyses indicated that supplementation with aspartate (ASP) or asparagine (ASN) could potentially ameliorate these metabolic deficiencies. Further metabolic assessments in Long COVID patients highlighted the significant downregulation of ASP in both blood and muscle, supporting our predictions.

Consequently, we propose that the combination of l-ornithine and l-aspartate (LOLA) offers a promising approach to alleviate metabolic symptoms in both ME/CFS and Long COVID patients. This study not only elucidates the shared metabolic pathways in ME/CFS and Long COVID but also positions LOLA as a viable candidate for future clinical trials.

Source: Gong-Hua Li, Feifei Han, Qing-Peng Kong, Wenzhong Xiao. Systems Modeling Reveals Shared Metabolic Dysregulation and Novel Therapeutic Treatments in ME/CFS and Long COVID. bioRxiv 2024.06.17.599450; doi: https://doi.org/10.1101/2024.06.17.599450 https://www.biorxiv.org/content/10.1101/2024.06.17.599450v1.full (Full text)

Transfer of IgG from Long COVID patients induces symptomology in mice

Abstract:

SARS-CoV-2 infections worldwide led to a surge in cases of Long COVID, a post-infectious syndrome. It has been hypothesized that autoantibodies play a crucial role in the development of Long COVID and other syndromes, such as fibromyalgia and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). In this study, we tested this hypothesis by passively transferring total IgG from Long COVID patients to mice.

Using Glial Fibrillary Acidic Protein (GFAP) and type-I interferon expression, we stratified patients into three Long COVID subgroups, each with unique plasma proteome signatures. Remarkably, IgG transfer from the two subgroups, which are characterized by higher plasma levels of neuronal proteins and leukocyte activation markers, induced pronounced and persistent sensory hypersensitivity with distinct kinetics. Conversely, IgG transfer from the third subgroup, which are characterized by enriched skeletal and cardiac muscle proteome profiles, reduced locomotor activity in mice without affecting their motor coordination.

These findings demonstrate that transfer of IgG from Long COVID patients to mice replicates disease symptoms, underscoring IgG’s causative role in Long COVID pathogenesis. This work proposes a murine model that mirrors Long COVID’s pathophysiological mechanisms, which may be used as a tool for screening and developing targeted therapeutics.

Source: Hung-Jen Chen, Brent Appelman, Hanneke Willemen, Amelie Bos, Judith Prado, Chiara. E. Geyer, Patrícia Silva Santos Ribeiro, Sabine Versteeg, Mads Larsen, Eline Schüchner, Marije K. Bomers, Ayesha H.A. Lavell, Amsterdam UMC COVID-19 biobank, Braeden Charlton, Rob Wüst, W. Joost Wiersinga, Michèle van Vugt, Gestur Vidarsson, Niels Eijkelkamp, Jeroen den Dunnen. Transfer of IgG from Long COVID patients induces symptomology in mice. bioRxiv 2024.05.30.596590; doi: https://doi.org/10.1101/2024.05.30.596590 https://www.biorxiv.org/content/10.1101/2024.05.30.596590v1.full (Full text)

A causal link between autoantibodies and neurological symptoms in long COVID

Summary:

Acute SARS-CoV-2 infection triggers the generation of diverse and functional autoantibodies (AABs), even after mild cases. Persistently elevated autoantibodies have been found in some individuals with long COVID (LC). Using a >21,000 human protein array, we identified diverse AAB targets in LC patients that correlated with their symptoms.

Elevated AABs to proteins in the nervous system were found in LC patients with neurocognitive and neurological symptoms. Purified Immunoglobulin G (IgG) samples from these individuals reacted with human pons tissue and were cross-reactive with mouse sciatic nerves, spinal cord, and meninges. Antibody reactivity to sciatic nerves and meninges correlated with patient-reported headache and disorientation. Passive transfer of IgG from patients to mice led to increased sensitivity and pain, mirroring patient-reported symptoms. Similarly, mice injected with IgG showed loss of balance and coordination, reflecting donor-reported dizziness. Our findings suggest that targeting AABs could benefit some LC patients.

Source: Keyla Santos Guedes de Sa, Julio Silva, Rafael Bayarri-Olmos, Ryan Brinda, Robert Alec Rath Constable, Patricia A. Colom Diaz, Dong il Kwon, Gisele Rodrigues, Li Wenxue, Christopher Baker, Bornali Bhattacharjee, Jamie Wood, Laura Tabacof, Yansheng Liu, David Putrino, Tamas L. Horvath, Akiko Iwasaki. A causal link between autoantibodies and neurological symptoms in long COVID. medRxiv 2024.06.18.24309100; doi: https://doi.org/10.1101/2024.06.18.24309100 https://www.medrxiv.org/content/10.1101/2024.06.18.24309100v1.full-text (Full text)

The German Multicenter Registry for ME/CFS (MECFS-R)

Abstract:

Background: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating multisystemic disease characterized by a complex, incompletely understood etiology.

Methods: To facilitate future clinical and translational research, a multicenter German ME/CFS registry (MECFS-R) was established to collect comprehensive, longitudinal, clinical, epidemiological, and laboratory data from adults, adolescents, and children in a web-based multilayer-secured database.

Results: Here, we present the research protocol and first results of a pilot cohort of 174 ME/CFS patients diagnosed at two specialized tertiary fatigue centers, including 130 (74.7%) adults (mean age 38.4; SD 12.6) and 43 (25.3%) pediatric patients (mean age 15.5; SD 4.2). A viral trigger was identified in 160/174 (92.0%) cases, with SARS-CoV-2 in almost half of them. Patients exhibited severe functional and social impairment, as reflected by a median Bell Score of 30.0 (IQR 30.0 to 40.0) and a poor health-related quality of life assessed with the Short Form-36 health survey, resulting in a mean score of 40.4 (SD 20.6) for physical function and 59.1 (SD 18.8) for mental health.

Conclusions: The MECFS-R provides important clinical information on ME/CFS to research and healthcare institutions. Paired with a multicenter biobank, it facilitates research on pathogenesis, diagnostic markers, and treatment options. Trial registration: ClinicalTrials.gov NCT05778006.

Source: Hieber H, Pricoco R, Gerrer K, Heindrich C, Wiehler K, Mihatsch LL, Haegele M, Schindler D, Donath Q, Christa C, Grabbe A, Kircher A, Leone A, Mueller Y, Zietemann H, Freitag H, Sotzny F, Warlitz C, Stojanov S, Hattesohl DBR, Hausruckinger A, Mittelstrass K, Scheibenbogen C, Behrends U. The German Multicenter Registry for ME/CFS (MECFS-R). J Clin Med. 2024 May 28;13(11):3168. doi: 10.3390/jcm13113168. PMID: 38892879; PMCID: PMC11172639. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11172639/ (Full text)