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COVID-19 and chronic fatigue syndrome: Is the worst yet to come?
Wostyn, P
Medical hypotheses. 2021;146:110469
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A proportion of COVID-19 patients develop post-COVID-19 syndrome, with long-term symptoms such as persistent fatigue, muscle pains, depressive symptoms, and non-restorative sleep, similar to myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). In this article the author presents his medical hypothesis that, in a subset of patients at least, post-COVID-19 fatigue syndrome may result from damage to olfactory (smell) sensory neurons, which in turn may lead to toxic build-up within the central nervous system (CNS) through congestion of the glymphatic system (the waste clearance system of the CNS). Loss of smell and altered sensation of taste have been reported in 33–80% of COVID-19 patients but the underlying mechanisms are not yet known. Most of these patients regain their sense of smell within 1-3 weeks, suggesting that the virus does not affect the olfactory neurons but their surrounding supporting cells. Some patients, however, do not regain their sense of smell for months which may point to the destruction of neurons. A decrease in olfactory neurons may affect the flow of the cerebrospinal fluid (CSF) in an area important for CSF drainage. This may cause an increase in intracranial pressure (idiopathic intracranial hypertension, IIH) and congestion of the glymphatic system, which have been associated with chronic fatigue syndrome, as well as with headaches and tinnitus, symptoms also commonly seen in COVID-19 patients. The author states that if this hypothesis is confirmed, glymphatic-lymphatic drainage therapies, such as osteopathy, should be recommended as early treatment for patients with post-COVID-19 fatigue syndrome.
Abstract
There has been concern about possible long-term sequelae resembling myalgic encephalomyelitis/chronic fatigue syndrome in COVID-19 patients. Clarifying the mechanisms underlying such a "post-COVID-19 fatigue syndrome" is essential for the development of preventive and early treatment methods for this syndrome. In the present paper, by integrating insights pertaining to the glymphatic system and the nasal cerebrospinal fluid outflow pathway with findings in patients with chronic fatigue syndrome, idiopathic intracranial hypertension, and COVID-19, I provide a coherent conceptual framework for understanding the pathophysiology of post-COVID-19 fatigue syndrome. According to this hypothesis, this syndrome may result from damage to olfactory sensory neurons, causing reduced outflow of cerebrospinal fluid through the cribriform plate, and further leading to congestion of the glymphatic system with subsequent toxic build-up within the central nervous system. I further postulate that patients with post-COVID-19 fatigue syndrome may benefit from cerebrospinal fluid drainage by restoring glymphatic transport and waste removal from the brain. Obviously, further research is required to provide further evidence for the presence of this post-viral syndrome, and to provide additional insight regarding the relative contribution of the glymphatic-lymphatic system to it. Other mechanisms may also be involved. If confirmed, the glymphatic-lymphatic system could represent a target in combating post-COVID-19 fatigue syndrome. Moreover, further research in this area could also provide new insights into the understanding of chronic fatigue syndrome.
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Systemic Perturbations in Amine and Kynurenine Metabolism Associated with Acute SARS-CoV-2 Infection and Inflammatory Cytokine Responses.
Lawler, NG, Gray, N, Kimhofer, T, Boughton, B, Gay, M, Yang, R, Morillon, AC, Chin, ST, Ryan, M, Begum, S, et al
Journal of proteome research. 2021;20(5):2796-2811
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Understanding the action of Covid-19 and the host response is paramount to developing personalised treatments and improving recovery rates. This cohort study of 64 individuals aimed to determine underlying biological signatures of individuals with severe and mild Covid-19, to potentially risk stratify patients and provide targeted treatments. The results showed that several biological signatures were disrupted with infection, some increased and some decreased and indicated possible liver, brain, and inflammatory disruptions. There was also evidence of a time-based pattern of biological disruptions, which may be of significance when looking at “long Covid” syndrome. It was concluded that identifying the hosts biological response to the virus offers insights into the viral action on the body. The action of Covid-19 on processes in the brain may indicate a secondary effect of the virus. Using biological markers to predict recovery of individuals suffering from “long Covid” may also be a possibility. This study could be used by healthcare professionals to understand which biological processes may be disrupted during Covid-19 infection, with the view to testing to understand who may be at risk of long-term complications post recovery.
Abstract
We performed quantitative metabolic phenotyping of blood plasma in parallel with cytokine/chemokine analysis from participants who were either SARS-CoV-2 (+) (n = 10) or SARS-CoV-2 (-) (n = 49). SARS-CoV-2 positivity was associated with a unique metabolic phenotype and demonstrated a complex systemic response to infection, including severe perturbations in amino acid and kynurenine metabolic pathways. Nine metabolites were elevated in plasma and strongly associated with infection (quinolinic acid, glutamic acid, nicotinic acid, aspartic acid, neopterin, kynurenine, phenylalanine, 3-hydroxykynurenine, and taurine; p < 0.05), while four metabolites were lower in infection (tryptophan, histidine, indole-3-acetic acid, and citrulline; p < 0.05). This signature supports a systemic metabolic phenoconversion following infection, indicating possible neurotoxicity and neurological disruption (elevations of 3-hydroxykynurenine and quinolinic acid) and liver dysfunction (reduction in Fischer's ratio and elevation of taurine). Finally, we report correlations between the key metabolite changes observed in the disease with concentrations of proinflammatory cytokines and chemokines showing strong immunometabolic disorder in response to SARS-CoV-2 infection.
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Diagnostic and Pharmacological Potency of Creatine in Post-Viral Fatigue Syndrome.
Ostojic, SM
Nutrients. 2021;13(2)
Abstract
Post-viral fatigue syndrome (PVFS) is a widespread chronic neurological disease with no definite etiological factor(s), no actual diagnostic test, and no approved pharmacological treatment, therapy, or cure. Among other features, PVFS could be accompanied by various irregularities in creatine metabolism, perturbing either tissue levels of creatine in the brain, the rates of phosphocreatine resynthesis in the skeletal muscle, or the concentrations of the enzyme creatine kinase in the blood. Furthermore, supplemental creatine and related guanidino compounds appear to impact both patient- and clinician-reported outcomes in syndromes and maladies with chronic fatigue. This paper critically overviews the most common disturbances in creatine metabolism in various PVFS populations, summarizes human trials on dietary creatine and creatine analogs in the syndrome, and discusses new frontiers and open questions for using creatine in a post-COVID-19 world.
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Role of mitochondria, oxidative stress and the response to antioxidants in myalgic encephalomyelitis/chronic fatigue syndrome: A possible approach to SARS-CoV-2 'long-haulers'?
Wood, E, Hall, KH, Tate, W
Chronic diseases and translational medicine. 2021;7(1):14-26
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Cases of chronic fatigue have been reported following recovery from Covid-19, in what is termed ‘Long Covid’, with symptoms likened to that of sufferers from chronic fatigue syndrome (CFS) and myalgic encephalomyelitis (ME). How CFS/ME develop and treatments may help to further understand Covid-19. This review study of 111 studies aimed to identify where urgent research is required to help understand the potential of chronic fatigue therapies in Covid-19. The study first reviewed disrupted cellular energy production in ME/CFS and increased presence of damaging oxidants. Current therapies for improving cellular energy production in CFS/ME were then reviewed and Ritalin, ubiquinone and mitoquinol mesylate were heavily featured. Antioxidant therapies in CFS/ME were reviewed and observations would suggest that trials in patients with long covid are needed. It was concluded that research in cellular energy production in CFS/ME has been increasing, however remains contradictory due to a lack of a definitive diagnosis, differing disease severity and the huge differences between patients who suffer from CFS/ME. Further research is required in ME/CFS and Covid-19. This study could be used by health care professionals to understand the importance of monitoring symptoms of fatigue post Covid-19 infection and the possible use of ME/CFS treatments.
Abstract
A significant number of SARS-CoV-2 (COVID-19) pandemic patients have developed chronic symptoms lasting weeks or months which are very similar to those described for myalgic encephalomyelitis/chronic fatigue syndrome. This study reviews the current literature and understanding of the role that mitochondria, oxidative stress and antioxidants may play in the understanding of the pathophysiology and treatment of chronic fatigue. It describes what is known about the dysfunctional pathways which can develop in mitochondria and their relationship to chronic fatigue. It also reviews what is known about oxidative stress and how this can be related to the pathophysiology of fatigue, as well as examining the potential for specific therapy directed at mitochondria for the treatment of chronic fatigue in the form of antioxidants. This study identifies areas which require urgent, further research in order to fully elucidate the clinical and therapeutic potential of these approaches.
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The neurological symptoms of COVID-19: a systematic overview of systematic reviews, comparison with other neurological conditions and implications for healthcare services.
Wildwing, T, Holt, N
Therapeutic advances in chronic disease. 2021;12:2040622320976979
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COVID-19 has been found to cause neurological manifestations in up to 50% of patients. The aim of this study was to inform future service provision for those who develop long-term neurological symptoms due to COVID-19, as well as exploring the effect of COVID-19 on health professionals’ perceptions towards those with symptoms of functional neurological disorder (FND). This study is a systematic overview of current systematic reviews which included 45 studies in qualitative synthesis. Results show that: - COVID-19 appears to be becoming chronic for some patients, presenting similar neurological symptoms to FND and to chronic fatigue syndrome; - the long-term neurological effects of COVID-19 may impact neurological and wider health care services; - the neurological symptoms seen in COVID-19 may affect health professionals’ perceptions of FND and chronic fatigue syndrome. Authors conclude that there is increasing evidence of the presence of long-COVID symptoms persisting beyond 3 months. Further research is recommended to explore whether the neurological symptoms of COVID-19 will improve acceptance and understanding of FND, or whether this will worsen the experience for those who suffer from FND.
Abstract
AIMS: In response to the rapid spread of COVID-19, this paper provides health professionals with better accessibility to available evidence, summarising findings from a systematic overview of systematic reviews of the neurological symptoms seen in patients with COVID-19. Implications of so-called 'Long Covid' on neurological services and primary care and similarities with other neurological disorders are discussed. METHODS Firstly, a systematic overview of current reviews of neurological symptoms of COVID-19 was conducted. Secondly, the implications of these findings are discussed in relation to the potential effect on neurological services and the similarities in the experience of patients with COVID-19 and those with other neurological disorders. A total of 45 systematic reviews were identified within seven databases, published between 11 April 2020 and 15 October 2020, following a search in June 2020, updated on 20 October 2020. RESULTS The results indicated that COVID-19 exhibits two types of neurological symptoms; life-threatening symptoms such as Guillain-Barre Syndrome (GBS) and encephalitis, and less devastating symptoms such as fatigue and myalgia. Many of these so-called lesser symptoms appear to be emerging as longer-term for some sufferers and have been recently labelled Long Covid. When compared, these less devastating symptoms are very similar to other neurological conditions such as chronic fatigue syndrome (CFS) and functional neurological disorder (FND). CONCLUSION Implications for neurological healthcare services in the United Kingdom (UK) may include longer waiting times and a need for more resources (including more qualified health professionals). There is also a possible change-effect on health professionals' perceptions of other neurological conditions such as CFS and FND. Future research is recommended to explore changes in health professionals' perceptions of neurological symptoms because of COVID-19.
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Vasculitis changes in COVID-19 survivors with persistent symptoms: an [18F]FDG-PET/CT study.
Sollini, M, Ciccarelli, M, Cecconi, M, Aghemo, A, Morelli, P, Gelardi, F, Chiti, A
European journal of nuclear medicine and molecular imaging. 2021;48(5):1460-1466
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The SARS-CoV-2 infection manifests with a broad spectrum of clinical patterns ranging from minimally or asymptomatic cases to mild illness, to severe infection, to critical disease. The aim of this study was to evaluate whether the radiopharmaceutical, 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG), was able to demonstrate a persistent inflammatory process in the vascular epithelium or in any other site. The study included Covid-19 patients who recovered but complained of unexplained persisting symptoms for more than 30 days during the follow-up visits. The patients where divided into two groups; the long Covid and control group. Results indicate that although the total vascular score was similar in the two groups, the target-to-blood pool ratio was significantly higher in three vascular regions (thoracic aorta, right iliac artery, and femoral arteries) in the long Covid than in controls. Authors conclude that their findings suggest that SARS-CoV-2 induces vascular inflammation, which may be responsible for persisting symptoms.
Abstract
PURPOSE Several patients experience unexplained persistent symptoms after SARS-CoV-2 recovering. We aimed at evaluating if 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) was able to demonstrate a persistent inflammatory process. METHODS Recovered adult COVID-19 patients, who complained unexplained persisting symptoms for more than 30 days during the follow-up visits, were invited to participate in the study. Patients fulfilling inclusion criteria were imaged by [18F]FDG positron emission tomography/computed tomography ([18F]FDG-PET/CT). Whole-body [18F]FDG-PET/CT, performed according to good clinical practice, was qualitatively (comparison with background/liver) and semi-quantitatively (target-to-blood pool ratio calculated as average SUVmax artery/average SUVmean inferior vena cava) analyzed. Negative follow-up [18F]FDG-PET/CT images of oncologic patients matched for age/sex served as controls. Mann-Whitney test was used to test differences between groups. SPSS version 26 was used for analyses. RESULTS Ten recovered SARS-CoV-2 patients (seven male and three females, median age 52 years, range 46-80) with persisting symptoms were enrolled in the study. Common findings at visual analysis were increased [18F]FDG uptake in bone marrow and blood vessels (8/10 and 6/10 cases, respectively). [18F]FDG uptake in bone marrow did not differ between cases and controls (p = 0.16). The total vascular score was similar in the two groups (p = 0.95). The target-to-blood pool ratio resulted higher in recovered SARS-CoV-2 patients than in controls. CONCLUSION Although the total vascular score was similar in the two groups, the target-to-blood pool ratio was significantly higher in three vascular regions (thoracic aorta, right iliac artery, and femoral arteries) in the recovered COVID-19 cohort than in controls, suggesting that SARS-CoV-2 induces vascular inflammation, which may be responsible for persisting symptoms.
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Historical Insight into Infections and Disorders Associated with Neurological and Psychiatric Sequelae Similar to Long COVID.
Stefano, GB
Medical science monitor : international medical journal of experimental and clinical research. 2021;27:e931447
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Literature shows that there are long-term symptoms and organ damage in patients with confirmed coronavirus disease 2019 (COVID-19) due to infection with severe acute respiratory syndrome coronavirus 2 that persist after the acute illness. The aim of this review was to present a historical overview of infections and disorders associated with the neurological and psychiatric sequelae that have shown similarities with long COVID. Historically, the common symptom of altered cognition has been reported during earlier pandemics. Pandemics discussed in this review include; influenza pandemics of 1889 and 1892 (Russian flu), Spanish flu pandemic (1918-1919), encephalitis lethargica, diphtheria, and myalgic encephalomyelitis (chronic fatigue syndrome or post-viral fatigue syndrome). Furthermore, literature shows that there are similarities between the symptoms of chronic fatigue syndrome and the brain fog of long COVID. Viral infection, cerebral hypoxia [reduced supply of oxygen to the brain), cognitive dysfunction, or brain fog may occur along a common pathway in the long-term pathogenesis of epidemic and pandemic infections, including COVID-19. Authors conclude that utilising data from past epidemics and pandemics may help to identify common acute and chronic syndromes, including neurological and psychiatric sequelae with similarities to the conditions currently described in patients with long COVID.
Abstract
Long-term sequelae of coronavirus disease 2019 (COVID-19) due to infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are now recognized. However, there is still a lack of consensus regarding the terminology for this emerging chronic clinical syndrome, which includes long COVID, chronic COVID syndrome, post-COVID-19 syndrome, post-acute COVID-19, and long-hauler COVID-19. In this review, I will use the term "long COVID". A review of the medical history and epidemiology of past pandemics and epidemics in modern literature review identifies common long-term post-infectious disorders, with the common finding of altered cognition. In the brain, the cerebral hypoxia induced by SARS-CoV-2 infection may be caused by mitochondrial dysfunction, resulting in "brain fog". Historically, the common symptom of altered cognition has been reported during earlier pandemics, which include the influenza pandemics of 1889 and 1892 (Russian flu), the Spanish flu pandemic (1918-1919), encephalitis lethargica, diphtheria, and myalgic encephalomyelitis (chronic fatigue syndrome or post-viral fatigue syndrome). There are similarities between chronic fatigue syndrome and the "brain fog" described in long COVID. During past viral epidemics and pandemics, a commonality of neural targets may have increased viral survival by conformational matching. The neurological and psychiatric sequelae of SARS-CoV-2 infection, or long COVID, may have emerged from neural effects that have emerged from an invertebrate and vertebrate virosphere. This review aims to present a historical overview of infections and disorders associated with neurological and psychiatric sequelae that have shown similarities with long COVID.
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SARS-CoV-2 and immune-microbiome interactions: Lessons from respiratory viral infections.
Cyprian, F, Sohail, MU, Abdelhafez, I, Salman, S, Attique, Z, Kamareddine, L, Al-Asmakh, M
International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases. 2021;105:540-550
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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an enveloped RNA beta-coronavirus. This virus caused the coronavirus disease 2019 (COVID-19) pandemic. The aim of this review was to investigate the relationship between microbiota, immunity, and COVID-19, with particular focus on how microbiome-associated immune crosstalk can shape outcome of COVID-19. The study included 118 articles which investigated or reviewed COVID-19 or coronavirus and the microbiome of the gut or respiratory tract. Findings indicate that: - an over-activated immune system leads to massive pulmonary damage in COVID-19 patients. - the effect of aging and comorbidities, and the use of antibiotics have an effect on the diversity of the microbiota. - the milieu of gut flora can exert influence on pulmonary immune responses. - a unique cross-talk exists between the pulmonary and gut microbial compartments. Authors conclude by highlighting the need of further studies that delineate the role of the microbiota and their products in the immune dysregulation observed in SARS-CoV-2 infections.
Abstract
By the beginning of 2020, infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) had rapidly evolved into an emergent worldwide pandemic, an outbreak whose unprecedented consequences highlighted many existing flaws within public healthcare systems across the world. While coronavirus disease 2019 (COVID-19) is bestowed with a broad spectrum of clinical manifestations, involving the vital organs, the respiratory system transpires as the main route of entry for SARS-CoV-2, with the lungs being its primary target. Of those infected, up to 20% require hospitalization on account of severity, while the majority of patients are either asymptomatic or exhibit mild symptoms. Exacerbation in the disease severity and complications of COVID-19 infection have been associated with multiple comorbidities, including hypertension, diabetes mellitus, cardiovascular disorders, cancer, and chronic lung disease. Interestingly, a recent body of evidence indicated the pulmonary and gut microbiomes as potential modulators for altering the course of COVID-19, potentially via the microbiome-immune system axis. While the relative concordance between microbes and immunity has yet to be fully elucidated with regards to COVID-19, we present an overview of our current understanding of COVID-19-microbiome-immune cross talk and discuss the potential contributions of microbiome-related immunity to SARS-CoV-2 pathogenesis and COVID-19 disease progression.
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Berberine reduces circulating inflammatory mediators in patients with severe COVID-19.
Zhang, BY, Chen, M, Chen, XC, Cao, K, You, Y, Qian, YJ, Yu, WK
The British journal of surgery. 2021;108(1):e9-e11
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Berberine has a long history in traditional Chinese medicine for the treatment of diarrhoea and gastroenteritis owing to its antimicrobial, antimotility and antisecretory properties. The aim of this study was to examine the effect of berberine on laboratory parameters in patients who have been hospitalised due to COVID-19. This study enrolled prospectively 39 patients with severe COVID-19 who were hospitalized, of which 18 patients were allocated to the berberine group and 17 to the control group. Patients in the berberine group were given berberine plus routine therapy within 14 days of admission, and those in the control group received only routine therapy. Results indicate that there wasn’t any significant difference between the two groups in relation to the laboratory parameters namely interleukin-6, tumour necrosis factor-alpha, C-reactive protein, procalcitonin and white blood cells levels within 14 days. In subgroup analyses of patients with diarrhoea, berberine significantly improved the changes in interleukin-6, tumour necrosis factor-alpha and C-reactive protein. Authors conclude that it is unclear whether berberine has any antiviral effect on SARS-CoV-2, and further experiments are needed to clarify this.
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Understanding Viral Infection Mechanisms and Patient Symptoms for the Development of COVID-19 Therapeutics.
Choi, HM, Moon, SY, Yang, HI, Kim, KS
International journal of molecular sciences. 2021;22(4)
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The outbreak of a novel coronavirus was reported in Wuhan, in the Hubei province of China, in December 2019. This virus was officially designated as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) because of its phylogenetic and taxonomic similarities to other coronaviruses. The aim of this review was to understand the viral infection mechanisms of SARS-CoV-2, the clinical features of Covid-19 and the mechanisms through which Covid-19 can be effectively treated with existing drugs. Literature shows that: • SARS-CoV-2 is usually transmitted by inhalation or contact with infected droplets. Inhaled droplets or aerosol carrying the virus then infect and spread through the respiratory tracts. • Severe inflammatory response is a remarkable feature of Covid-19 symptoms. This is caused by delayed viral clearance, which induces chronic systemic inflammation and widespread tissue damage, even leading to cytokine storms. • The incubation period is generally 5-6 days, but it ranges from one day to as much as two weeks. • Interstitial pneumonia and subsequent acute respiratory distress syndrome are the leading causes of death in patients with Covid-19. • There is no licensed treatment for Covid-19, only a combination of antiviral and anti-inflammatory drug treatments are being used. Authors conclude that their finding may provide new insights into the development of therapeutics by understanding the various clinical and basic research studies currently underway.
Abstract
Coronavirus disease 2019 (COVID-19), caused by the SARS-CoV-2 virus, has become a worldwide pandemic. Symptoms range from mild fever to cough, fatigue, severe pneumonia, acute respiratory distress syndrome (ARDS), and organ failure, with a mortality rate of 2.2%. However, there are no licensed drugs or definitive treatment strategies for patients with severe COVID-19. Only antiviral or anti-inflammatory drugs are used as symptomatic treatments based on clinician experience. Basic medical researchers are also trying to develop COVID-19 therapeutics. However, there is limited systematic information about the pathogenesis of COVID-19 symptoms that cause tissue damage or death and the mechanisms by which the virus infects and replicates in cells. Here, we introduce recent knowledge of time course changes in viral titers, delayed virus clearance, and persistent systemic inflammation in patients with severe COVID-19. Based on the concept of drug reposition, we review which antiviral or anti-inflammatory drugs can effectively treat COVID-19 patients based on progressive symptoms and the mechanisms inhibiting virus infection and replication.