Tag: long covid pathophysiology

Mild SARS-CoV-2 infection results in long-lasting microbiota instability

Abstract:

Viruses targeting mammalian cells can indirectly alter the gut microbiota, potentially compounding their phenotypic effects. Multiple studies have observed a disrupted gut microbiota in severe cases of SARS-CoV-2 infection that require hospitalization. Yet, despite demographic shifts in disease severity resulting in a large and continuing burden of non-hospitalized infections, we still know very little about the impact of mild SARS-CoV-2 infection on the gut microbiota in the outpatient setting. To address this knowledge gap, we longitudinally sampled 14 SARS-CoV-2 positive subjects who remained outpatient and 4 household controls. SARS-CoV-2 cases exhibited a significantly less stable gut microbiota relative to controls, as long as 154 days after their positive test. These results were confirmed and extended in the K18-hACE2 mouse model, which is susceptible to SARS-CoV-2 infection. All of the tested SARS-CoV-2 variants significantly disrupted the mouse gut microbiota, including USA-WA1/2020 (the original variant detected in the United States), Delta, and Omicron. Surprisingly, despite the fact that the Omicron variant caused the least severe symptoms in mice, it destabilized the gut microbiota and led to a significant depletion in Akkermansia muciniphila. Furthermore, exposure of wild-type C57BL/6J mice to SARS-CoV-2 disrupted the gut microbiota in the absence of severe lung pathology.

IMPORTANCE Taken together, our results demonstrate that even mild cases of SARS-CoV-2 can disrupt gut microbial ecology. Our findings in non-hospitalized individuals are consistent with studies of hospitalized patients, in that reproducible shifts in gut microbial taxonomic abundance in response to SARS-CoV-2 have been difficult to identify. Instead, we report a long-lasting instability in the gut microbiota. Surprisingly, our mouse experiments revealed an impact of the Omicron variant, despite producing the least severe symptoms in genetically susceptible mice, suggesting that despite the continued evolution of SARS-CoV-2 it has retained its ability to perturb the intestinal mucosa. These results will hopefully renew efforts to study the mechanisms through which Omicron and future SARS-CoV-2 variants alter gastrointestinal physiology, while also considering the potentially broad consequences of SARS-CoV-2-induced microbiota instability for host health and disease.

Source: Vaibhav Upadhyay, Rahul Suryawanshi, Preston Tasoff, Maria McCavitt-Malvido, G. Renuka Kumar, Victoria Wong Murray, Cecilia Noecker, Jordan E. Bisanz, Yulin Hswen, Connie Ha, Bharat Sreekumar, Irene P. Chen, Susan V Lynch, Melanie Ott, Sulggi Lee, Peter J. Turnbaugh. Mild SARS-CoV-2 infection results in long-lasting microbiota instability. bioRxiv 2022.12.07.519508; doi: https://doi.org/10.1101/2022.12.07.519508  https://www.biorxiv.org/content/10.1101/2022.12.07.519508v1.full (Full text)

Signatures of Mitochondrial Dysfunction and Impaired Fatty Acid Metabolism in Plasma of Patients with Post-Acute Sequelae of COVID-19 (PASC)

Abstract:

Exercise intolerance is a major manifestation of post-acute sequelae of severe acute respiratory syndrome coronavirus infection (PASC, or “long-COVID”). Exercise intolerance in PASC is associated with higher arterial blood lactate accumulation and lower fatty acid oxidation rates during graded exercise tests to volitional exertion, suggesting altered metabolism and mitochondrial dysfunction. It remains unclear whether the profound disturbances in metabolism that have been identified in plasma from patients suffering from acute coronavirus disease 2019 (COVID-19) are also present in PASC.

To bridge this gap, individuals with a history of previous acute COVID-19 infection that did not require hospitalization were enrolled at National Jewish Health (Denver, CO, USA) and were grouped into those that developed PASC (n = 29) and those that fully recovered (n = 16). Plasma samples from the two groups were analyzed via mass spectrometry-based untargeted metabolomics and compared against plasma metabolic profiles of healthy control individuals (n = 30). Observational demographic and clinical data were retrospectively abstracted from the medical record.

Compared to plasma of healthy controls or individuals who recovered from COVID-19, PASC plasma exhibited significantly higher free- and carnitine-conjugated mono-, poly-, and highly unsaturated fatty acids, accompanied by markedly lower levels of mono-, di- and tricarboxylates (pyruvate, lactate, citrate, succinate, and malate), polyamines (spermine) and taurine. Plasma from individuals who fully recovered from COVID-19 exhibited an intermediary metabolic phenotype, with milder disturbances in fatty acid metabolism and higher levels of spermine and taurine. Of note, depletion of tryptophan-a hallmark of disease severity in COVID-19-is not normalized in PASC patients, despite normalization of kynurenine levels-a tryptophan metabolite that predicts mortality in hospitalized COVID-19 patients.

In conclusion, PASC plasma metabolites are indicative of altered fatty acid metabolism and dysfunctional mitochondria-dependent lipid catabolism. These metabolic profiles obtained at rest are consistent with previously reported mitochondrial dysfunction during exercise, and may pave the way for therapeutic intervention focused on restoring mitochondrial fat-burning capacity.

Source: Guntur VP, Nemkov T, de Boer E, Mohning MP, Baraghoshi D, Cendali FI, San-Millán I, Petrache I, D’Alessandro A. Signatures of Mitochondrial Dysfunction and Impaired Fatty Acid Metabolism in Plasma of Patients with Post-Acute Sequelae of COVID-19 (PASC). Metabolites. 2022 Oct 26;12(11):1026. doi: 10.3390/metabo12111026. PMID: 36355108; PMCID: PMC9699059. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9699059/ (Full text)

Severe Neuro-COVID is associated with peripheral immune signatures, autoimmunity and neurodegeneration: a prospective cross-sectional study

Abstract:

Growing evidence links COVID-19 with acute and long-term neurological dysfunction. However, the pathophysiological mechanisms resulting in central nervous system involvement remain unclear, posing both diagnostic and therapeutic challenges. Here we show outcomes of a cross-sectional clinical study (NCT04472013) including clinical and imaging data and corresponding multidimensional characterization of immune mediators in the cerebrospinal fluid (CSF) and plasma of patients belonging to different Neuro-COVID severity classes.

The most prominent signs of severe Neuro-COVID are blood-brain barrier (BBB) impairment, elevated microglia activation markers and a polyclonal B cell response targeting self-antigens and non-self-antigens. COVID-19 patients show decreased regional brain volumes associating with specific CSF parameters, however, COVID-19 patients characterized by plasma cytokine storm are presenting with a non-inflammatory CSF profile. Post-acute COVID-19 syndrome strongly associates with a distinctive set of CSF and plasma mediators. Collectively, we identify several potentially actionable targets to prevent or intervene with the neurological consequences of SARS-CoV-2 infection.

Source: Etter MM, Martins TA, Kulsvehagen L, Pössnecker E, Duchemin W, Hogan S, Sanabria-Diaz G, Müller J, Chiappini A, Rychen J, Eberhard N, Guzman R, Mariani L, Melie-Garcia L, Keller E, Jelcic I, Pargger H, Siegemund M, Kuhle J, Oechtering J, Eich C, Tzankov A, Matter MS, Uzun S, Yaldizli Ö, Lieb JM, Psychogios MN, Leuzinger K, Hirsch HH, Granziera C, Pröbstel AK, Hutter G. Severe Neuro-COVID is associated with peripheral immune signatures, autoimmunity and neurodegeneration: a prospective cross-sectional study. Nat Commun. 2022 Nov 9;13(1):6777. doi: 10.1038/s41467-022-34068-0. PMID: 36351919; PMCID: PMC9645766.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9645766/ (Full text)

The role of gut microbiota in etiopathogenesis of long COVID syndrome

To the editor.

COVID-19, a novel infectious disease caused by SARS-CoV-2 first emerged on November 17, 2019 had a high fatality rate and affected millions of people around the world [1]. The involvement of lung gut axis and the identification of viral RNA in feces of infected patients has drawn attention to a possible fecal-oral transmission route of SARS-CoV-2 [2].

Recent research shows a potential connection between long-term COVID-19 and dysbiosis of the gut flora. Long COVID-19 infection or post-acute COVID-19 syndrome is seen after weeks or months after the initial COVID-19 infection is characterized by complications and lingering symptoms such as fatigue, muscle weakness, and sleeplessness. Up to 3 out of 4 individuals report at least one symptom six months after recovering from COVID-19 infection, making it a relatively prevalent condition [3]. Long COVID may develop as a result of a heightened immune response, cell damage, or physiological effects of COVID-19 infection.

The gut microbiome, the billions of bacteria, fungus, and other microbes that live in the digestive tract, has been linked to COVID-19 severity and may possibly have an impact on the healing process, according to a growing body of research [4]. Researchers at the Chinese University of Hong Kong’s Center for Gut Microbiota Research discovered a clue in 2020.

When compared to healthy controls, persons with COVID-19 had unique changes in their gut microbiota, or the population of bacteria that live in their gut [5]. Early reports from Wuhan suggested that 2–10% of COVID-19 patients experienced gastrointestinal (GI) symptoms, such as diarrhoea, however a recent meta-analysis found that up to 20% of patients with COVID-19 had GI symptoms. SARS-CoV-2 virus was found in anal swabs and stool samples in over half of COVID-19 patients, suggesting that the digestive tract could be an extrapulmonary location for virus multiplication and activity [6, 7].

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Source: Kaushik P, Kumari M, Singh NK, Suri A. The role of gut microbiota in etiopathogenesis of long COVID syndrome. Horm Mol Biol Clin Investig. 2022 Nov 1. doi: 10.1515/hmbci-2022-0079. Epub ahead of print. PMID: 36317311. https://www.degruyter.com/document/doi/10.1515/hmbci-2022-0079/html (Full text)

SARS-CoV-2 promotes microglial synapse elimination in human brain organoids

Abstract:

Neuropsychiatric manifestations are common in both the acute and post-acute phase of SARS-CoV-2 infection, but the mechanisms of these effects are unknown. In a newly established brain organoid model with innately developing microglia, we demonstrate that SARS-CoV-2 infection initiate neuronal cell death and cause a loss of post-synaptic termini. Despite limited neurotropism and a decelerating viral replication, we observe a threefold increase in microglial engulfment of postsynaptic termini after SARS-CoV-2 exposure.

We define the microglial responses to SARS-CoV-2 infection by single cell transcriptomic profiling and observe an upregulation of interferon-responsive genes as well as genes promoting migration and synapse engulfment. To a large extent, SARS-CoV-2 exposed microglia adopt a transcriptomic profile overlapping with neurodegenerative disorders that display an early synapse loss as well as an increased incident risk after a SARS-CoV-2 infection. Our results reveal that brain organoids infected with SARS-CoV-2 display disruption in circuit integrity via microglia-mediated synapse elimination and identifies a potential novel mechanism contributing to cognitive impairments in patients recovering from COVID-19.

Source: Samudyata, Oliveira AO, Malwade S, Rufino de Sousa N, Goparaju SK, Gracias J, Orhan F, Steponaviciute L, Schalling M, Sheridan SD, Perlis RH, Rothfuchs AG, Sellgren CM. SARS-CoV-2 promotes microglial synapse elimination in human brain organoids. Mol Psychiatry. 2022 Oct 5:1–12. doi: 10.1038/s41380-022-01786-2. Epub ahead of print. PMID: 36198765; PMCID: PMC9533278.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9533278/ (Full text)

Is Long COVID Syndrome a Transient Mitochondriopathy Newly Discovered: Implications of CPET

Abstract:

The new outbreak of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has an impact worldwide, primarily as a medical emergency. Even that the total constellation is considered as a pandemic of acute respiratory disease, coronavirus disease 2019 (COVID-19) gives rise to dysfunction in multiple organs (e.g., brain, lungs, heart, muscles) that impairs cardiopulmonary (CP) function. Parallel to the CP consequences of COVID-19 is a significant reduction in physical activity.

Cardiopulmonary exercise testing (CPET) is daily used in clinical practice to define prognosis, provide risk stratification and treatment strategy. As such, the significance of CPET is crucial concerning clinical assessments of COVID-19 patients. Furthermore, new studies aim at understanding the effects of SARS-CoV-2 infection in long term. Multiple studies have investigated the cardiopulmonary function and impairment of exercise endurance in such patients, as well as a possible prolonged physical impairment. With this review, we summarize the COVID-19-associated pathophysiology for the Long COVID (LC) syndrome as well as the importance of performing CPET.

Source: Stefanos G. Sakellaropoulos, Muhammad Ali, Athanasios Papadis, Muhemin Mohammed, Andreas Mitsis, Zaza Zivzivadze. Is Long COVID Syndrome a Transient Mitochondriopathy Newly Discovered: Implications of CPET. Cardiology Research, ISSN 1923-2829 print, Volume 13, Number 5, October 2022, pages 264-267.  https://www.cardiologyres.org/index.php/Cardiologyres/article/view/1419/1360 (Full text)

Brain 18F-FDG PET imaging in outpatients with post-COVID-19 conditions: findings and associations with clinical characteristics

Abstract:

Background: Brain 18F-FDG PET imaging has the potential to provide an objective assessment of brain involvement in post-COVID-19 conditions but previous studies of heterogeneous patient series yield inconsistent results. The current study aimed to investigate brain 18F-FDG PET findings in a homogeneous series of outpatients with post-COVID-19 conditions and to identify associations with clinical patient characteristics.

Methods: We retrospectively included 28 consecutive outpatients who presented with post-COVID-19 conditions between September 2020 and May 2022 and who satisfied the WHO definition, and had a brain 18F-FDG PET for suspected brain involvement but had not been hospitalized for COVID-19. A voxel-based group comparison with 28 age- and sex-matched healthy controls was performed (p-voxel at 0.005 uncorrected, p-cluster at 0.05 FWE corrected) and identified clusters were correlated with clinical characteristics.

Results: Outpatients with post-COVID-19 conditions exhibited diffuse hypometabolism predominantly involving right frontal and temporal lobes including the orbito-frontal cortex and internal temporal areas. Metabolism in these clusters was inversely correlated with the number of symptoms during the initial infection (r = – 0.44, p = 0.02) and with the duration of symptoms (r = – 0.39, p = 0.04). Asthenia and cardiovascular, digestive, and neurological disorders during the acute phase and asthenia and language disorders during the chronic phase (p ≤ 0.04) were associated with these hypometabolic clusters.

Conclusion: Outpatients with post-COVID-19 conditions exhibited extensive hypometabolic right fronto-temporal clusters. Patients with more numerous symptoms during the initial phase and with a longer duration of symptoms were at higher risk of persistent brain involvement.

Source: Goehringer F, Bruyere A, Doyen M, Bevilacqua S, Charmillon A, Heyer S, Verger A. Brain 18F-FDG PET imaging in outpatients with post-COVID-19 conditions: findings and associations with clinical characteristics. Eur J Nucl Med Mol Imaging. 2022 Nov 2. doi: 10.1007/s00259-022-06013-2. Epub ahead of print. PMID: 36322190. https://link.springer.com/article/10.1007/s00259-022-06013-2 (Full text)

Beyond COVID-19 and SARS-CoV-2, cardiovascular outcomes of “long covid” from a pathological perspective – a look back and road ahead

Abstract:

With the decrease in severity of COVID-19 there is a sense of relief in the general population. However, there has been an increased incidence of cardiovascular and other organ complications post-infection, which have raised concerns about long COVID. The term “long COVID” was first used by Perego on social media to denote the persistence of symptoms weeks or months after initial SARS-CoV-2 infection and the term ‘long haulers’ was first described by Watson and by Yong to identify post-COVID conditions.

There has been an increased incidence of sudden cardiac death and MI post-COVID-19 in healthy individuals, sports persons and prominent movie stars. Potential mechanisms contributing to the pathophysiology of post-acute COVID-19 may include 1) Damage to tissues and cells that are important for blood flow, so clotting of blood is increased. 2) Persistence of fragments of virus or its sub-particles/ protein material in a wide range of body sites and, 3) an immune system gone haywire.

As the majority of countries across the globe are easing coronavirus precautionary measures, there is an urgent need by health care organizations and policymakers worldwide to generate awareness by educating the public at large, about the ill effects of long-COVID and varied types of post-acute sequelae of COVID-19.

Source: Aden D, Zaheer S, Kumar R, Raj S, Khan T, Varshney S. Beyond COVID-19 and SARS-CoV-2, cardiovascular outcomes of “long covid” from a pathological perspective – a look back and road ahead. Pathol Res Pract. 2022 Sep 29;239:154144. doi: 10.1016/j.prp.2022.154144. Epub ahead of print. PMID: 36242969; PMCID: PMC9519512.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9519512/ (Full text)

SARS-CoV-2, long COVID, prion disease and neurodegeneration

Introduction:

On the last day of the year 2019 a novel Betacoronavirus (2019-nCov), now known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and causing the highly transmissible and lethal pneumonia COVID-19 was first reported in Wuhan, Hubei Province in Central China (Huang et al., ; Fu et al., ; Lu and Sun, ). Since then ongoing research and long-term studies of the sequelae of SARS-CoV-2 infection have indicated that post-infection, recovery from COVID-19 and/or COVID-19 aftermath is associated with long-term physiological and neurological deficits known generically as “long COVID” (Roy et al., ; Ahmad et al., ; Baazaoui and Iqbal, ). Multiple independent epidemiological and clinical studies further indicate that SARS-CoV-2 infection and “long COVID” strongly correlate with the onset of progressive neurological disturbances that include Alzheimer’s disease (AD), prion disease (PrD) and other neurodegenerative disorders. These are apparent: (i) especially in aged and/or senile COVID-19 patients; (ii) in patients experiencing overlapping or inter-current illnesses that include heart disease, diabetes, hypertension, neuropsychiatric and other age-related neurological disorders; and (iii) in those COVID-19 patients who have experienced a particularly virulent and/or a near fatal episode of SARS-CoV-2 infection (Farheen et al., ; Flud et al., ; Fu et al., ). Conversely, increasing numbers of epidemiological studies suggest that elderly people with neurological deficits commonly observed in AD are highly vulnerable to SARS-CoV-2 infection, and especially the development of more severe forms of COVID-19 disease (Chiricosta et al., ; Hsu et al., ; Fu et al., ). The recent finding that the SARS-CoV-2 “S1” spike protein essential for viral infectivity contains prion-like domains associated with immune-evasion and the promotion of protein aggregation and aggregate “seeding” is particularly intriguing (Baazaoui and Iqbal, ; Bernardini et al., ; Tetz and Tetz, ). Based on these and other very recent findings this “Opinion” paper will: (i) address our current understanding of the emerging role of SARS-CoV-2 infection with “long COVID” with special reference to AD and PrD; (ii) will review the latest findings of the SARS-CoV-2 “S1” spike protein and its preferred interaction with the ubiquitous angiotensin converting enzyme-2 (ACE2) receptor (ACE2R); and (iii) will highlight the interplay of the molecular biology and neuropathology of SARS-CoV-2 with the unusual and immune-evasive character of prion neurobiology, AD and PrD.

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Source: Zhao Y, Jaber VR, Lukiw WJ. SARS-CoV-2, long COVID, prion disease and neurodegeneration. Front Neurosci. 2022 Sep 27;16:1002770. doi: 10.3389/fnins.2022.1002770. PMID: 36238082; PMCID: PMC9551214.  Zhao Y, Jaber VR, Lukiw WJ. SARS-CoV-2, long COVID, prion disease and neurodegeneration. Front Neurosci. 2022 Sep 27;16:1002770. doi: 10.3389/fnins.2022.1002770. PMID: 36238082; PMCID: PMC9551214. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9551214/ (Full text)

Post-COVID syndrome, inflammation, and diabetes

Abstract:

The raging COVID-19 pandemic is in its third year of global impact. The SARS CoV 2 virus has a high rate of spread, protean manifestations, and a high morbidity and mortality in individuals with predisposing risk factors. The pathophysiologic mechanisms involve a heightened systemic inflammatory state, cardiometabolic derangements, and varying degrees of glucose intolerance. The latter can be evident as significant hyperglycemia leading to new-onset diabetes or worsening of preexisting disease.

Unfortunately, the clinical course beyond the acute phase of the illness may persist in the form of a variety of symptoms that together form the so-called “Long COVID” or “Post-COVID Syndrome”. It is thought that a chronic, low-grade inflammatory and immunologic state persists during this phase, which may last for weeks or months. Although numerous insights have been gained into COVID-related hyperglycemia and diabetes, its prediction, course, and management remain to be fully elucidated.

Source: Rizvi AA, Kathuria A, Al Mahmeed W, Al-Rasadi K, Al-Alawi K, Banach M, Banerjee Y, Ceriello A, Cesur M, Cosentino F, Galia M, Goh SY, Janez A, Kalra S, Kempler P, Lessan N, Lotufo P, Papanas N, Santos RD, Stoian AP, Toth PP, Viswanathan V, Rizzo M; CArdiometabolic Panel of International experts on Syndemic COvid-19 (CAPISCO). Post-COVID syndrome, inflammation, and diabetes. J Diabetes Complications. 2022 Oct 6;36(11):108336. doi: 10.1016/j.jdiacomp.2022.108336. Epub ahead of print. PMID: 36228563; PMCID: PMC9534783. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9534783/ (Full text)