Mitochondrial Dysfunction in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

ME/CFS is a debilitating multisystem disorder of unclear etiology that affects many individuals worldwide. One of its hallmark symptoms is prolonged fatigue following exertion, a feature also observed in long COVID, suggesting an underlying dysfunction in energy production in both conditions. Here, mitochondrial dysfunction and its potential pathogenetic role in these disorders are reviewed.

Source: Syed AM, Karius AK, Ma J, Wang PY, Hwang PM. Mitochondrial Dysfunction in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Physiology (Bethesda). 2025 Feb 17. doi: 10.1152/physiol.00056.2024. Epub ahead of print. PMID: 39960432. https://journals.physiology.org/doi/abs/10.1152/physiol.00056.2024 (Full text available as PDF file)

Dietary Supplementation for Fatigue Symptoms in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)-A Systematic Review

Abstract:

Background/Objectives: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a complex neuroimmunological disorder with limited treatment options. Despite the widespread use of Dietary Supplements (DSs) among ME/CFS patients to alleviate fatigue and associated symptoms, evidence remains inconclusive. This systematic review aims to provide an updated synthesis of the efficacy of DS interventions and explore possible mechanisms underlying their therapeutic effects.

Methods: This systematic review was conducted according to PRISMA guidelines. Several databases (Ebsco Host, PubMed, Scopus, Google Scholar) were used for the systematic search, which was based on the broad search terms ME/CFS and DS with a focus on publications between 1994 and 2024. The primary outcome was fatigue, with additional considerations including psychological well-being, physical activity, and biochemical markers. Two independent researchers screened the studies for eligibility in a multi-stage process and assessed quality and bias using Cochrane’s risk of bias tools (RoB-2, ROBINS-I).

Results: Fourteen studies (N = 809) of heterogeneous designs were included, showing a high risk of bias, mostly due to missing data and selection bias. While some interventions (L-carnitine and guanidinoacetic acid, oxaloacetate, CoQ10-selenium combination, NADH and NADH-CoQ10 combination) showed significant reductions in fatigue, methodological limitations, like small sample sizes and missing data, prevent firm conclusions. Mixed results were reported for secondary outcomes like cognitive function and inflammatory markers. Six studies noted adverse effects, including nausea and insomnia.

Conclusions: Though some DSs showed potential in reducing fatigue in ME/CFS, methodological limitations and inconsistent results hinder definitive conclusions. Future research should improve diagnostic criteria and include more diverse populations.

Source: Dorczok MC, Mittmann G, Mossaheb N, Schrank B, Bartova L, Neumann M, Steiner-Hofbauer V. Dietary Supplementation for Fatigue Symptoms in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)-A Systematic Review. Nutrients. 2025 Jan 28;17(3):475. doi: 10.3390/nu17030475. PMID: 39940333; PMCID: PMC11819863. https://pmc.ncbi.nlm.nih.gov/articles/PMC11819863/ (Full text)

Language Matters: What Not to Say to Patients with Long COVID, Myalgic Encephalomyelitis/Chronic Fatigue Syndrome, and Other Complex Chronic Disorders

Abstract:

People with Long COVID, myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), and other complex chronic disorders consistently report having difficulty obtaining effective and compassionate medical care and being disbelieved, judged, gaslighted, and even dismissed by healthcare professionals. We believe that these adversarial interactions and language are more likely to arise when healthcare professionals are confronting complex chronic illnesses without proper training, diagnostic biomarkers, or FDA-approved therapies.
These problematic conversations between practitioners and patients often involve specific words and phrases—termed the “never-words”—can leave patients in significant emotional distress and negatively impact the clinician–patient relationship and recovery. Seeking to prevent these destructive interactions, we review key literature on best practices for difficult clinical conversations and discuss the application of these practices for people with Long COVID, ME/CFS, dysautonomia, and other complex chronic disorders. We provide recommendations for alternative, preferred phrasing to the never-words, which can enhance therapeutic relationship and chronic illness patient care via compassionate, encouraging, and non-judgmental language.
Source: Smyth NJ, Blitshteyn S. Language Matters: What Not to Say to Patients with Long COVID, Myalgic Encephalomyelitis/Chronic Fatigue Syndrome, and Other Complex Chronic Disorders. International Journal of Environmental Research and Public Health. 2025; 22(2):275. https://doi.org/10.3390/ijerph22020275 https://www.mdpi.com/1660-4601/22/2/275 (Full text)

The Microbiota-Gut-Brain Axis in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Narrative Review of an Emerging Field

Abstract:

The intricate relationship between gut microbiota and the brain has emerged as a pivotal area of research, particularly in understanding myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). This complex condition is characterized by debilitating fatigue, cognitive dysfunction, and a wide array of systemic manifestations, posing significant challenges for diagnosis and treatment. Recent studies highlight the microbiota-gut-brain axis as a crucial pathway in ME/CFS pathophysiology, suggesting that alterations in gut microbial composition may impact immune responses, neurochemical signaling, and neuronal health.

This narrative review systematically explores English-language scholarly articles from January 1995 to January 2025, utilizing databases such as PubMed, Scopus, and Web of Science. The findings underscore the potential for targeted therapeutic interventions aimed at correcting gut dysbiosis. As research progresses, a deeper understanding of the microbiota-gut-brain connection could lead to innovative approaches for managing ME/CFS, ultimately enhancing the quality of life for affected individuals.

Source: El-Sehrawy AAMA, Ayoub II, Uthirapathy S, Ballal S, Gabble BC, Singh A, V K, Panigrahi R, Kamali M, Khosravi M. The Microbiota-Gut-Brain Axis in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Narrative Review of an Emerging Field. Eur J Transl Myol. 2025 Feb 12. doi: 10.4081/ejtm.2025.13690. Epub ahead of print. PMID: 39937103. https://pubmed.ncbi.nlm.nih.gov/39937103/

Cerebral Blood Flow in Orthostatic Intolerance

Abstract:

Cerebral blood flow (CBF) is vital for delivering oxygen and nutrients to the brain. Many forms of orthostatic intolerance (OI) involve impaired regulation of CBF in the upright posture, which results in disabling symptoms that decrease quality of life. Because CBF is not easy to measure, rises in heart rate or drops in blood pressure are used as proxies for abnormal CBF. These result in diagnoses such as postural orthostatic tachycardia syndrome and orthostatic hypotension. However, in many other OI syndromes such as myalgic encephalomyelitis/chronic fatigue syndrome and long COVID, heart rate and blood pressure are frequently normal despite significant drops in CBF. This often leads to the incorrect conclusion that there is nothing hemodynamically abnormal in these patients and thus no explanation or treatment is needed. There is a need to measure CBF, as orthostatic hypoperfusion is the shared pathophysiology for all forms of OI. In this review, we examine the literature studying CBF dysfunction in various syndromes with OI and evaluate methods of measuring CBF including transcranial Doppler ultrasound, extracranial cerebral blood flow ultrasound, near infrared spectroscopy, and wearable devices.

Source: Khan MS, Miller AJ, Ejaz A, Molinger J, Goyal P, MacLeod DB, Swavely A, Wilson E, Pergola M, Tandri H, Mills CF, Raj SR, Fudim M. Cerebral Blood Flow in Orthostatic Intolerance. J Am Heart Assoc. 2025 Feb 3:e036752. doi: 10.1161/JAHA.124.036752. Epub ahead of print. PMID: 39895557. https://www.ahajournals.org/doi/10.1161/JAHA.124.036752 (Full text)

Tetrahydrobiopterin in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Friend or Foe?

Abstract:

Myalgic Encephalomyelitis or Chronic Fatigue Syndrome (ME/CFS) is a chronic multisystem disease characterized by severe muscle fatigue, pain, dizziness, and brain fog. The two most common symptoms are post-exertional malaise (PEM) and orthostatic intolerance (OI). ME/CFS patients with OI (ME+OI) suffer from dizziness or faintness due to a sudden drop in blood pressure while maintaining an upright posture. Clinical research has demonstrated that patients with OI display severe cardiovascular abnormalities resulting in reduced effective blood flow in the cerebral blood vessels. However, despite intense investigation, it is not known why the effective cerebral blood flow is reduced in OI patients. Based on our recent findings, we observed that tetrahydrobiopterin (BH4) metabolism was highly dysregulated in ME+OI patients. In the current review article, we attempted to summarize our recent findings on BH4 metabolism to shed light on the molecular mechanisms of OI.

Source: Rahman AFMT, Benko A, Bulbule S, Gottschalk CG, Arnold LA, Roy A. Tetrahydrobiopterin in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Friend or Foe? Biomolecules. 2025 Jan 10;15(1):102. doi: 10.3390/biom15010102. PMID: 39858496; PMCID: PMC11763651. https://pmc.ncbi.nlm.nih.gov/articles/PMC11763651/ (Full text)

Machine learning and multi-omics in precision medicine for ME/CFS

Abstract:

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a complex and multifaceted disorder that defies simplistic characterisation. Traditional approaches to diagnosing and treating ME/CFS have often fallen short due to the condition’s heterogeneity and the lack of validated biomarkers. The growing field of precision medicine offers a promising approach which focuses on the genetic and molecular underpinnings of individual patients.

In this review, we explore how machine learning and multi-omics (genomics, transcriptomics, proteomics, and metabolomics) can transform precision medicine in ME/CFS research and healthcare. We provide an overview on machine learning concepts for analysing large-scale biological data, highlight key advancements in multi-omics biomarker discovery, data quality and integration strategies, while reflecting on ME/CFS case study examples. We also highlight several priorities, including the critical need for applying robust computational tools and collaborative data-sharing initiatives in the endeavour to unravel the biological intricacies of ME/CFS.

Source: Huang K, Lidbury BA, Thomas N, Gooley PR, Armstrong CW. Machine learning and multi-omics in precision medicine for ME/CFS. J Transl Med. 2025 Jan 14;23(1):68. doi: 10.1186/s12967-024-05915-z. PMID: 39810236. Huang K, Lidbury BA, Thomas N, Gooley PR, Armstrong CW. Machine learning and multi-omics in precision medicine for ME/CFS. J Transl Med. 2025 Jan 14;23(1):68. doi: 10.1186/s12967-024-05915-z. PMID: 39810236. https://translational-medicine.biomedcentral.com/articles/10.1186/s12967-024-05915-z (Full text)

Key Pathophysiological Role of Skeletal Muscle Disturbance in Post COVID and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): Accumulated Evidence

Abstract:

Background: Recent studies provide strong evidence for a key role of skeletal muscle pathophysiology in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). In a 2021 review article on the pathophysiology of ME/CFS, we postulated that hypoperfusion and ischemia can result in excessive sodium and calcium overload in skeletal muscles of ME/CFS patients to cause mitochondrial damage. Since then, experimental evidence has been provided that supports this concept.

Methods: We collect, summarize and discuss the current state of knowledge for the key role of skeletal muscle pathophysiology. We try to explain which risk factors and mechanisms are responsible for a subgroup of patients with post COVID syndrome (PCS) to develop ME/CFS (PC-ME/CFS).

Results: Mitochondrial dysfunction is a long-held assumption to explain cardinal symptoms of ME/CFS. However, mitochondrial dysfunction could not be convincingly shown in leukocytes. By contrast, recent studies provide strong evidence for mitochondrial dysfunction in skeletal muscle tissue in ME/CFS. An electron microscopy study could directly show damage of mitochondria in skeletal muscle of ME/CFS patients with a preferential subsarcolemmal localization but not in PCS. Another study shows signs of skeletal muscle damage and regeneration in biopsies taken one day after exercise in PC-ME/CFS. The simultaneous presence of necroses and signs of regeneration supports the concept of repeated damage. Other studies correlated diminished hand grip strength (HGS) with symptom severity and prognosis. A MRI study showed that intracellular sodium in muscles of ME/CFS patients is elevated and that levels correlate inversely with HGS. This finding corroborates our concept of sodium and consecutive calcium overload as cause of muscular and mitochondrial damage caused by enhanced proton-sodium exchange due to anaerobic metabolism and diminished activity of the sodium-potassium-ATPase. The histological investigations in ME/CFS exclude ischemia by microvascular obstruction, viral presence or immune myositis. The only known exercise-induced mechanism of damage left is sodium induced calcium overload. If ionic disturbance and mitochondrial dysfunction is severe enough the patient may be captured in a vicious circle. This energy deficit is the most likely cause of exertional intolerance and post exertional malaise and is further aggravated by exertion.

Conclusion: Based on this pathomechanism, future treatment approaches should focus on normalizing the cause of ionic disbalance. Current treatment strategies targeting hypoperfusion have the potential to improve the dysfunction of ion transporters.

Source: Scheibenbogen C, Wirth KJ. Key Pathophysiological Role of Skeletal Muscle Disturbance in Post COVID and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): Accumulated Evidence. J Cachexia Sarcopenia Muscle. 2025 Feb;16(1):e13669. doi: 10.1002/jcsm.13669. PMID: 39727052; PMCID: PMC11671797. https://pmc.ncbi.nlm.nih.gov/articles/PMC11671797/ (Full text)

Chronic inflammatory response syndrome: a review of the evidence of clinical efficacy of treatment

Abstract:

Chronic Inflammatory Response Syndrome (CIRS) is an acquired medical condition characterized by innate immune dysregulation following respiratory exposure to water-damaged buildings (WDB). This chronic syndrome involves a range of symptoms that simultaneously affecting multiple organ systems. The purpose of this literature review was to search the published literature for successful treatments for chronic inflammatory response syndrome, an under-recognized, underdiagnosed, multisymptom multisystem illness that can affect up to 25% of the population, thus representing a silent epidemic.

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), a common misdiagnosis for CIRS, is an entity that has broader awareness within the medical community despite the absence of a defined etiology, biomarkers or a treatment protocol that reverses the underlying conditions. Therefore, the search also included treatments for ME/CFS and sick building syndrome (SBS). Thirteen articles referenced treatment for CIRS, and 22 articles referenced treatment for CFS.

The only treatment with documented clinical efficacy was the Shoemaker Protocol, which was described in 11 of the 13 articles. This treatment protocol exhibits superior outcomes compared with the treatment protocols for ME/CFS.

Source: Dooley M, Vukelic A, Jim L. Chronic inflammatory response syndrome: a review of the evidence of clinical efficacy of treatment. Ann Med Surg (Lond). 2024 Nov 8;86(12):7248-7254. doi: 10.1097/MS9.0000000000002718. PMID: 39649915; PMCID: PMC11623837. https://pmc.ncbi.nlm.nih.gov/articles/PMC11623837/ (Full text)

Qigong and Tai Chi for ME/CFS: A Systematic Review of Randomized Controlled Trials

Abstract:

Objective: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a chronic and debilitating illness with symptoms such as post-exertional malaise and cognitive dysfunction that can be challenging for patients to manage independently. Randomized controlled trials (RCTs) have examined mind-body and psychological approaches that teach patients coping skills for mitigating ME/CFS symptoms, including emerging literature on Qigong or Tai Chi instruction programs. This systematic review aims to summarize the characteristics of these trials and highlight potential areas for future optimization and refinement.

Methods: Ovid MEDLINE, Embase.com, Web of Science Core Collection, Cochrane CENTRAL, PsycINFO via Ovid, and ClinicalTrials.gov were searched in April 2023 using controlled vocabulary and keywords for the following eligibility criteria: Sample (ME/CFS), Design (RCT), Behavioral Intervention (mind-body or psychological interventions). Data extraction and reporting followed Cochrane and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

Results: “Qigong” and “Tai Chi” yielded 142 and 80 abstracts, respectively. Of the 222 abstracts, full texts were available for 5 RCTs of Qigong (k = 5; N = 481). Notably, no trials of Tai Chi utilized a randomized control design. Among the 5 Qigong RCTs, the publication range was from 2012 to 2023. Details regarding intervention components and effects were summarized. Qigong intervention sessions (median = 12, mode = 10, 12) tended to last between 1-2 hours and occur across 5-12 weeks (median = 7, mode = 5). The Qigong interventions were all delivered in groups and incorporated at-home practice. Daily practice was a requirement (k = 4) or an advisement (k = 1). Patient-reported outcomes suggest an emerging evidence base for diffuse benefits on physical and emotional health outcomes.

Conclusions: Qigong interventions are promising, yet relatively understudied, in improving ME/CFS symptom severity and frequency. Future trials must implement standardized eligibility criteria for ME/CFS history, integrate Qigong or Tai Chi with other empirically supported mind-body and psychological practices, and assess long-term resiliency outcomes relevant to ME/CFS survivorship.

Source: Markwart M, Felsenstein D, Mehta DH, Sethi S, Tsuchiyose E, Lydson M, Yeh GY, Hall DL. Qigong and Tai Chi for ME/CFS: A Systematic Review of Randomized Controlled Trials. Glob Adv Integr Med Health. 2024 Nov 7;13:27536130241275607. doi: 10.1177/27536130241275607. PMID: 39524182; PMCID: PMC11544658. https://pmc.ncbi.nlm.nih.gov/articles/PMC11544658/ (Full text)