Evidence browser

Dissecting the Molecular Mechanisms Surrounding Post-COVID-19 Syndrome and Neurological Features.

Mohamed, Mohamed S, Johansson, Anton, Jonsson, Jörgen et al.·International journal of molecular sciences·2022

This study reviews how the virus that causes COVID-19 may damage the nervous system and brain, leading to long-term symptoms similar to those seen in other coronavirus outbreaks. The authors identify specific brain mechanisms—involving inflammation, nerve cell communication problems, and hormone regulation—that could explain why some people develop persistent neurological symptoms after COVID-19. These findings suggest potential targets for future treatments.

Inflammation From Peripheral Organs to the Brain: How Does Systemic Inflammation Cause Neuroinflammation?

Sun, Yuanjie, Koyama, Yoshihisa, Shimada, Shoichi·Frontiers in aging neuroscience·2022

This review explores how inflammation in the body's organs—like the gut, lungs, or joints—can trigger inflammation in the brain. The authors describe several pathways by which this happens, including damage to the protective barrier around the brain, activation of immune cells in the brain, and communication through nerves connecting organs to the brain. ME/CFS is highlighted as one disease where this peripheral-to-brain inflammation mechanism may be important.

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Stellate ganglion block reduces symptoms of Long COVID: A case series.

Liu, Luke D, Duricka, Deborah L·Journal of neuroimmunology·2022

This small study looked at a procedure called a stellate ganglion block, which uses local anesthetic to temporarily quiet the nerve signals in the neck that control your 'fight or flight' response. Two Long COVID patients received this procedure, and their symptoms—including fatigue, brain fog, and dizziness upon standing—improved. The authors suggest that an imbalance in the autonomic nervous system (the system that controls automatic body functions) may be contributing to Long COVID symptoms.

NeuroinflammationGut MicrobiomeImmune System

Mucosal Immunity and the Gut-Microbiota-Brain-Axis in Neuroimmune Disease.

Sterling, Kathryn G, Dodd, Griffin Kutler, Alhamdi, Shatha et al.·International journal of molecular sciences·2022

This review article examines the connection between gut bacteria, immunity, and the brain in diseases like ME/CFS. The authors explain that the bacteria in our gut can communicate with our brain through chemical signals and nerves, but this communication can be disrupted in certain illnesses. They focus on how the immune system in the gut lining controls which bacteria thrive there, and how changes in these bacterial communities might contribute to neuroimmune diseases.

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

Renz-Polster, Herbert, Tremblay, Marie-Eve, Bienzle, Dorothee et al.·Frontiers in cellular neuroscience·2022

This study suggests that ME/CFS might be caused by problems with certain support cells in the brain called glia, which help protect and maintain nerve cells. The researchers reviewed existing research on two key ME/CFS symptoms—feeling worse after activity and reduced blood flow to the brain—and found evidence that brain cell dysfunction could explain many of the different problems seen in ME/CFS.

NeuroinflammationPost-Exertional Malaise

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COVID-19 and chronic fatigue syndrome: Is the worst yet to come?

Wostyn, Peter·Medical hypotheses·2021

This paper proposes a theory about why some people develop prolonged fatigue after COVID-19 that resembles ME/CFS. The author suggests that COVID-19 may damage nerve cells in the nose, which could reduce the brain's ability to clear out waste products, leading to toxic buildup and fatigue. The paper calls for research to test whether treatments that help drain fluid from around the brain might help patients with post-COVID fatigue.

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Dorsal root ganglia: fibromyalgia pain factory?

Martínez-Lavín, Manuel·Clinical rheumatology·2021

This article explores whether structures called dorsal root ganglia (DRG)—small nerve clusters along the spine—might be the main source of pain in fibromyalgia. These ganglia contain pain-sensing nerve cells and immune molecules that can become overactive. Recent evidence suggests that in some fibromyalgia patients, these nerve clusters show signs of damage and increased pain signaling.

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Moderate, intermittent voluntary exercise in a model of Gulf War Illness improves cognitive and mood function with alleviation of activated microglia and astrocytes, and enhanced neurogenesis in the hippocampus.

Kodali, Maheedhar, Mishra, Vikas, Hattiangady, Bharathi et al.·Brain, behavior, and immunity·2021

Researchers tested whether moderate exercise three times a week could help rats with a Gulf War Illness-like condition improve their memory, mood, and thinking skills. After 13 weeks, the exercising rats showed better memory and less anxiety, and their brains showed less inflammation and more growth of new brain cells. This suggests that gentle, part-time exercise might help people with similar conditions improve brain function.

NeuroinflammationPost-Exertional Malaise

Persistent Brainstem Dysfunction in Long-COVID: A Hypothesis.

Yong, Shin Jie·ACS chemical neuroscience·2021

This paper suggests that long-COVID symptoms may be caused by damage to the brainstem, a part of the brain that controls basic functions like breathing, heart rate, and digestion. The authors propose that the coronavirus may directly infect the brainstem or cause inflammation there, and because brain cells heal slowly, this damage could persist long after the initial infection. This theory could help explain why long-COVID patients experience lasting fatigue, breathing problems, and other widespread symptoms.

[Intestinal flora and neurological disorders].

Tang, Qianqian, Cao, Lihua·Sheng wu gong cheng xue bao = Chinese journal of biotechnology·2021

Your gut bacteria (microbiome) communicate with your brain through multiple pathways, including immune signals and nerve connections. When this gut-brain communication goes wrong, it may contribute to various neurological conditions, including chronic fatigue syndrome. This review summarizes what scientists know about how imbalanced gut bacteria might affect the nervous system and cause disease.

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Improvement Effects of Myelophil on Symptoms of Chronic Fatigue Syndrome in a Reserpine-Induced Mouse Model.

Song, Ji-Hye, Won, Seul-Ki, Eom, Geun-Hyang et al.·International journal of molecular sciences·2021

Researchers tested a herbal mixture called myelophil (made from two traditional medicinal plants) in mice engineered to show ME/CFS-like symptoms including fatigue, pain, and depression. The treatment improved all three symptoms and appeared to work by increasing important brain chemicals like dopamine and serotonin, reducing inflammation, and protecting against cell damage. While these results are encouraging, this study was only in mice, so it's too early to know if the same benefits would occur in people with ME/CFS.

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

Mackay, Angus·Frontiers in neurology·2021

This study proposes that long-term fatigue following COVID-19 works similarly to ME/CFS—both may result from severe infection triggering dysfunction in a brain region called the hypothalamic paraventricular nucleus (PVN). In people genetically susceptible to this condition, the stress from COVID-19 infection could overwhelm this brain center, making it oversensitive to everyday stressors and causing the fatigue, post-exertional malaise, and other symptoms characteristic of ME/CFS.

NeuroinflammationPost-Exertional Malaise

Historical Insight into Infections and Disorders Associated with Neurological and Psychiatric Sequelae Similar to Long COVID.

Stefano, George B·Medical science monitor : international medical journal of experimental and clinical research·2021

This review examines how long COVID causes long-term symptoms similar to those seen after other viral infections throughout history, particularly focusing on 'brain fog' and difficulty thinking clearly. By looking at past pandemics like the 1918 flu and other viral illnesses, researchers found that many infections can cause similar cognitive problems and fatigue that persist long after the initial infection. The study suggests that viruses may damage the brain's energy-producing structures (mitochondria), leading to reduced oxygen in the brain and chronic symptoms like those seen in ME/CFS and long COVID.

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[Electroacupuncture improves cognitive function by inhibiting NF-κB activity in rats with chronic fatigue syndrome].

Feng, Chu-Wen, Qu, Yuan-Yuan, Sun, Zhong-Ren et al.·Zhen ci yan jiu = Acupuncture research·2021

This study tested whether electroacupuncture (a form of acupuncture with electrical stimulation) could help rats with chronic fatigue syndrome recover cognitive abilities like memory and learning. The researchers found that electroacupuncture reduced inflammation in the brain's memory center (hippocampus) and improved the rats' ability to learn and remember, likely by blocking a inflammatory protein called NF-κB.

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[Imaging and Manipulation of Stem and Progenitor Cells for Revealing the Novel Mechanism of Local Tissue Maintenance in the Brain].

Kataoka, Yosky·Yakugaku zasshi : Journal of the Pharmaceutical Society of Japan·2021

This study examined special cells in the brain called glial progenitor cells that help maintain healthy brain tissue and manage inflammation. Researchers used imaging technology to track these cells and discovered that when these cells are removed, the brain develops harmful inflammation and immune activation. The findings suggest these cells may play a protective role and could be targeted to treat conditions associated with brain inflammation, including chronic fatigue syndrome.

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An Adrenalectomy Mouse Model Reflecting Clinical Features for Chronic Fatigue Syndrome.

Lee, Jin-Seok, Jeon, Yoo-Jin, Park, Samuel-Young et al.·Biomolecules·2020

Researchers tested three different mouse models to find the best one for studying ME/CFS. They found that removing the adrenal glands (small organs that produce stress hormones) in mice created fatigue and pain symptoms most similar to ME/CFS, while other common models mainly produced depression-like behaviors. The adrenal-removed mice also showed specific brain changes involving inflammation and stress hormone pathways.

Neuroimmunology: What Role for Autoimmunity, Neuroinflammation, and Small Fiber Neuropathy in Fibromyalgia, Chronic Fatigue Syndrome, and Adverse Events after Human Papillomavirus Vaccination?

Ryabkova, Varvara A, Churilov, Leonid P, Shoenfeld, Yehuda·International journal of molecular sciences·2019

This review explores three interconnected biological processes that may cause fibromyalgia and chronic fatigue syndrome (ME/CFS): the immune system attacking the body's own tissues, inflammation in the nervous system, and damage to small nerve fibers. The authors propose that these three mechanisms work together and may explain why patients experience widespread pain, extreme fatigue, and other symptoms like brain fog and sleep problems. They also examine whether similar mechanisms might explain some adverse reactions to HPV vaccination.

Myalgic encephalomyelitis or chronic fatigue syndrome: how could the illness develop?

Morris, Gerwyn, Maes, Michael, Berk, Michael et al.·Metabolic brain disease·2019

This study proposes a theory for how ME/CFS might develop, starting with an infection that triggers lasting problems in the body's immune system and stress response. The authors suggest that in genetically vulnerable people, this leads to a chain of events: increased inflammation, intestinal problems that allow bacteria-related substances to enter the bloodstream, nervous system dysfunction, and eventually a state where the immune system becomes exhausted and less able to fight back. This model tries to explain why ME/CFS patients have the specific symptoms and lab abnormalities doctors observe.

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Epstein-Barr Virus dUTPase Induces Neuroinflammatory Mediators: Implications for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Williams PhD, Marshall V, Cox, Brandon, Lafuse PhD, William P et al.·Clinical therapeutics·2019

This study explores whether a protein from the Epstein-Barr virus (EBV) may trigger brain inflammation in ME/CFS patients. Researchers found that this viral protein can change how brain cells function and alter important chemical pathways involved in energy, mood, and pain processing. The findings suggest that in some ME/CFS patients, this viral protein might contribute to fatigue, pain, and thinking difficulties.

Myalgia and chronic fatigue syndrome following immunization: macrophagic myofasciitis and animal studies support linkage to aluminum adjuvant persistency and diffusion in the immune system.

Gherardi, Romain K, Crépeaux, Guillemette, Authier, François-Jérome·Autoimmunity reviews·2019

This review examines whether ME/CFS could be triggered by aluminum-containing substances in certain vaccines. The authors present evidence that aluminum particles may persist in immune cells and travel to the brain, potentially causing the cognitive problems, muscle pain, and fatigue seen in ME/CFS. They argue this condition represents a broader category of vaccine-related adverse effects called ASIA.