Immune mechanisms underlying COVID-19 pathology and post-acute sequelae of SARS-CoV-2 infection (PASC)

Abstract:

With a global tally of more than 500 million cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections to date, there are growing concerns about the post-acute sequelae of SARS-CoV-2 infection (PASC), also known as long COVID. Recent studies suggest that exaggerated immune responses are key determinants of the severity and outcomes of the initial SARS-CoV-2 infection as well as subsequent PASC. The complexity of the innate and adaptive immune responses in the acute and post-acute period requires in-depth mechanistic analyses to identify specific molecular signals as well as specific immune cell populations which promote PASC pathogenesis.

In this review, we examine the current literature on mechanisms of immune dysregulation in severe COVID-19 and the limited emerging data on the immunopathology of PASC. While the acute and post-acute phases may share some parallel mechanisms of immunopathology, it is likely that PASC immunopathology is quite distinct and heterogeneous, thus requiring large-scale longitudinal analyses in patients with and without PASC after an acute SARS-CoV-2 infection. By outlining the knowledge gaps in the immunopathology of PASC, we hope to provide avenues for novel research directions that will ultimately lead to precision therapies which restore healthy immune function in PASC patients.

Source: Sindhu MohandasPrasanna JagannathanTimothy J HenrichZaki A SherifChristian BimeErin QuinlanMichael A PortmanMarila GennaroJalees RehmanRECOVER Mechanistic Pathways Task Force (2023) Immune mechanisms underlying COVID-19 pathology and post-acute sequelae of SARS-CoV-2 infection (PASC) eLife 12:e86014. https://elifesciences.org/articles/86014 (Full text)

Rheumatology and Long COVID: lessons from the study of fibromyalgia

Abstract:

Rheumatology, such as other subspecialties, has both a unique perspective to offer as well as an evolving role to play in the global COVID-19 pandemic. Our field has already contributed meaningfully to the development and repurposing of many of the immune-based therapeutics which are now standard treatments for severe forms of the disease as well as to the understanding of the epidemiology, risk factors and natural history of COVID-19 in immune-mediated inflammatory diseases. Still in evolution is our potential to contribute to burgeoning research efforts in the next phase of the pandemic: the syndrome of postacute sequelae of COVID-19 or Long COVID. While our field brings many assets to the study of Long COVID including our expertise in the investigation of chronic inflammation and autoimmunity, our Viewpoint focuses on the strong similarities between fibromyalgia (FM) and Long COVID. While one can speculate on how embracing and confident practising rheumatologists already are regarding these interrelationships, we assert that in the emerging field of Long COVID the potential lessons from the field of fibromyalgia care and research have been underappreciated and marginalised and most importantly now deserve a critical appraisal.

Source: Clauw DJ, Calabrese L. Rheumatology and Long COVID: lessons from the study of fibromyalgia. Ann Rheum Dis. 2023 May 25:ard-2023-224250. doi: 10.1136/ard-2023-224250. Epub ahead of print. PMID: 37230736. https://ard.bmj.com/content/early/2023/05/24/ard-2023-224250 (Full text)

Autonomic Nervous System Affection Due to Post Covid Syndrome

Identification of the Effects of Post Covid Syndrome on the Autonomic Nervous System With Heart Rate Variability

Post-Covid syndrome is defined as symptoms that develop in addition to respiratory symptoms in individuals who have had Covid-19 infection for more than 12 weeks. Symptoms such as fatigue, headache, cognitive impairment, dyspnea, heart palpitations, heat intolerance, digestive system disorders, sleep disorders, dermal problems, orthostatic intolerance come to the fore in individuals with post-Covid syndrome. It has been tried to be revealed in some studies that Covid-19 infection affects the autonomic nervous system (ANS) and the relationship between Post-Covid 19 syndrome and ANS dysfunction.
Heart rate variability (HRV) measurement method can be used to evaluate ANS activity. HRV is a non-invasive method and is a measure of the change in heart rate over a period of time. HRV is a scalar quantity that shows the time between two beats of the heart and defines the oscillations between the R-R intervals. In HRV measurements, time-dependent and frequency-dependent measurement results are obtained and from these measurements, time-dependent RMSSD (square root of the square of the difference of the R-R intervals) and frequency-dependent high-frequency (HF) and low frequency (LF) measurement components are used in relation to the sympathetic nervous system (CNS) and parasympathetic nervous system (PSS). HRV can be measured in short-term (5 minutes) in terms of measurement time.
The aim of this study is to clearly reveal the relationship between Post-Covid 19 syndrome and ANS dysfunction and to provide standardization related to HRV measurement method and sub-parameters.
Source: Ali Veysel Özden, M.D. Bahçeşehir University. Istanbul, Beşiktaş, Turkey, 34000. ICH GCP US Clinical Trials Registry, Clinical Trial NCT05502094 https://ichgcp.net/clinical-trials-registry/NCT05502094

Changes in the proteomics of exhaled breath condensate under the influence of inhaled hydrogen in patients with post-COVID syndrome.

Abstract:

Purpose. To study the effect of inhalation therapy with an active form of hydrogen (APH) on the protein composition of exhaled air condensate (EAC) in patients with post-COVID syndrome (PCS).

Material and methods. A randomized controlled parallel prospective study included 60 patients who had a novel coronavirus infection (COVID-19, COronaVIrus Disease 2019) with PCD during the recovery period, had clinical manifestations of chronic fatigue syndrome and received standard therapy according to the protocol for managing patients with chronic fatigue syndrome. The patients were divided into 2 groups: group 1 (main) – 30 people who received standard therapy and APV inhalations (device “SUISONIA”, Japan) for 10 days, and group 2 (control) – 30 medical workers who received only standard therapy. Patients in both groups were comparable in terms of gender and mean age. All participants in the study on the 1st and 10th days. samples were taken from the CVV.

Results. A total of 478 proteins and 1350 peptides were identified using high resolution mass spectrometry. The number of proteins in samples after APV therapy, on average, is 12% more than before treatment. An analysis of the distribution of proteins in different groups of patients showed that only half of these proteins (112) are common for all groups of samples and are detected in EVC before, after, and regardless of hydrogen therapy. In addition to the qualitative difference in the protein compositions of CEA in different groups, quantitative changes in the concentration of 36 proteins (mainly structural and protective) were also detected, which together made it possible to reliably distinguish between subgroups before and after treatment. It is important to note that among these proteins there are participants in the processes of blood coagulation (a-1-antitrypsin), mediated by chemokines and cytokines of inflammation,

Conclusion. The use of hydrogen therapy can contribute to the switching of a number of physiological processes, which may affect the success of restorative treatment in PKD. In particular, the obtained results indicate the activation of aerobic synthesis of adenosine triphosphate in mitochondria by hydrogen therapy, which correlates well with the decrease in blood lactate levels detected by laboratory studies in the studied patients. At the same time, it is important that this therapy can inhibit pro-inflammatory activity, negatively affecting the coagulation processes and signaling pathways of integrins and apoptosis, and, in addition, activate protective pathways, the tricarboxylic acid cycle, FAS signaling, and purine metabolism, which can be significant. for effective recovery after suffering COVID-19.

Source: Ryabokon, A. M.; Zakharova, N. V.; Indeikina, M. I.; Kononikhin, A. S.; Shogenova, L. V.; Medvedev, O. S.; Kostinov, M. P.; Svitich, O. A.; Ibaraki, K.; Maehara, H.; Nikolaev, E. N.; Varfolomeev, S. D.; Chuchalin, A. G. Changes in the proteomics of exhaled breath condensate under the influence of inhaled hydrogen in patients with post-COVID syndrome. Cardiovascular Therapy and Prevention (Russian Federation) ; 22(3):50-59, 2023. https://www.researchgate.net/publication/369954717_Changes_in_the_proteomics_of_exhaled_breath_condensate_under_the_influence_of_inhaled_hydrogen_in_patients_with_post-COVID_syndrome

Fighting Post-COVID and ME/CFS – development of curative therapies

Abstract:

The sequela of COVID-19 include a broad spectrum of symptoms that fall under the umbrella term post-COVID-19 condition or syndrome (PCS). Immune dysregulation, autoimmunity, endothelial dysfunction, viral persistence, and viral reactivation have been identified as potential mechanisms.

However, there is heterogeneity in expression of biomarkers, and it is unknown yet whether these distinguish different clinical subgroups of PCS. There is an overlap of symptoms and pathomechanisms of PCS with postinfectious myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).

No curative therapies are available for neither ME/CFS nor PCS. The mechanisms identified so far provide targets for therapeutic interventions.

To accelerate the development of therapies, we propose evaluating drugs targeting different mechanisms in clinical trial networks using harmonized diagnostic and outcome criteria and subgrouping patients based on a thorough clinical profiling including a comprehensive diagnostic and biomarker phenotyping.

Source: Carmen Scheibenbogen, Judith T. Bellmann-Strobl, Cornelia Heindrich, Kirsten Wittke, Elisa Stein, Christiana Franke, Harald Prüss, Hannah Preßler, Marie-Luise Machule, Heinrich Audebert, Carsten Finke, Hanna G. Zimmerman,  Birgit Sawitzki, Christian Meisel, Markus Tölle, Anne Krüger, Anna C. Aschenbrenner, Joachim L. Schultz, Marc D. Beyer, Markus Ralser, Michael Mülleder, Leif E. Sander, Frank Konietschke, Friedemann Paul, Silvia Stojanov, Lisa Bruckert, Dennis M. Hedderich, Franziska Knolle, Gabriela Riemekasten, Maria J. Vehreschild, Oliver A. Cornely, Uta Behrends and Susen Burock.  Fighting Post-COVID and ME/CFS – development of curative therapies. Frontiers in Medicine, Sec. Infectious Diseases: Pathogenesis and Therapy: Volume 10 – 2023. https://www.frontiersin.org/articles/10.3389/fmed.2023.1194754/abstract

 

ME/CFS and Long COVID share similar symptoms and biological abnormalities: road map to the literature

Summary:

Some patients remain unwell for months after “recovering” from acute COVID-19. They develop persistent fatigue, cognitive problems, headaches, disrupted sleep, myalgias and arthralgias, post-exertional malaise, orthostatic intolerance and other symptoms that greatly interfere with their ability to function and that can leave some people housebound and disabled. The illness (Long COVID) is similar to myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) as well as to persisting illnesses that can follow a wide variety of other infectious agents and following major traumatic injury. Together, these illnesses are projected to cost the U.S. trillions of dollars.

In this review, we first compare the symptoms of ME/CFS and Long COVID, noting the considerable similarities and the few differences. We then compare in extensive detail the underlying pathophysiology of these two conditions, focusing on abnormalities of the central and autonomic nervous system, lungs, heart, vasculature, immune system, gut microbiome, energy metabolism and redox balance. This comparison highlights how strong the evidence is for each abnormality, in each illness, and helps to set priorities for future investigation. The review provides a current road map to the extensive literature on the underlying biology of both illnesses.

Source: Anthony L. Komaroff and W. Ian Lipkin. ME/CFS and Long COVID share similar symptoms and biological abnormalities: road map to the literature. Front. Med., 02 June 2023. Sec. Infectious Diseases: Pathogenesis and Therapy. Volume 10 – 2023 | https://doi.org/10.3389/fmed.2023.1187163 (Full text)

Neuroinflammation After COVID-19 With Persistent Depressive and Cognitive Symptoms

Abstract:

Importance: Persistent depressive symptoms, often accompanied by cognitive symptoms, commonly occur after COVID-19 illness (hereinafter termed COVID-DC, DC for depressive and/or cognitive symptoms). In patients with COVID-DC, gliosis, an inflammatory change, was suspected, but measurements of gliosis had not been studied in the brain for this condition.

Objective: To determine whether translocator protein total distribution volume (TSPO VT), a marker of gliosis that is quantifiable with positron emission tomography (PET), is elevated in the dorsal putamen, ventral striatum, prefrontal cortex, anterior cingulate cortex, and hippocampus of persons with COVID-DC.

Design, setting, and participants: This case-control study conducted at a tertiary care psychiatric hospital in Canada from April 1, 2021, to June 30, 2022, compared TSPO VT of specific brain regions in 20 participants with COVID-DC with that in 20 healthy controls. The TSPO VT was measured with fluorine F 18-labeled N-(2-(2-fluoroethoxy)benzyl)-N-(4-phenoxypyridin-3-yl)acetamide ([18F]FEPPA) PET.

Main outcomes and measures: The TSPO VT was measured in the dorsal putamen, ventral striatum, prefrontal cortex, anterior cingulate cortex, and hippocampus. Symptoms were measured with neuropsychological and psychological tests, prioritizing outcomes related to striatal function.

Results: The study population included 40 participants (mean [SD] age, 32.9 [12.3] years). The TSPO VT across the regions of interest was greater in persons with COVID-DC (mean [SD] age, 32.7 [11.4] years; 12 [60%] women) compared with healthy control participants (mean [SD] age, 33.3 [13.9] years; 11 [55%] women): mean (SD) difference, 1.51 (4.47); 95% CI, 0.04-2.98; 1.51 divided by 9.20 (17%). The difference was most prominent in the ventral striatum (mean [SD] difference, 1.97 [4.88]; 95% CI, 0.36-3.58; 1.97 divided by 8.87 [22%]) and dorsal putamen (mean difference, 1.70 [4.25]; 95% CI, 0.34-3.06; 1.70 divided by 8.37 [20%]). Motor speed on the finger-tapping test negatively correlated with dorsal putamen TSPO VT (r, -0.53; 95% CI, -0.79 to -0.09), and the 10 persons with the slowest speed among those with COVID-DC had higher dorsal putamen TSPO VT than healthy persons by 2.3 (2.30 divided by 8.37 [27%]; SD, 2.46; 95% CI, 0.92-3.68).

Conclusions and relevance: In this case-control study, TSPO VT was higher in patients with COVID-DC. Greater TSPO VT is evidence for an inflammatory change of elevated gliosis in the brain of an individual with COVID-DC. Gliosis may be consequent to inflammation, injury, or both, particularly in the ventral striatum and dorsal putamen, which may explain some persistent depressive and cognitive symptoms, including slowed motor speed, low motivation or energy, and anhedonia, after initially mild to moderate COVID-19 illness.

Source: Braga J, Lepra M, Kish SJ, Rusjan PM, Nasser Z, Verhoeff N, Vasdev N, Bagby M, Boileau I, Husain MI, Kolla N, Garcia A, Chao T, Mizrahi R, Faiz K, Vieira EL, Meyer JH. Neuroinflammation After COVID-19 With Persistent Depressive and Cognitive Symptoms. JAMA Psychiatry. 2023 May 31:e231321. doi: 10.1001/jamapsychiatry.2023.1321. Epub ahead of print. PMID: 37256580; PMCID: PMC10233457. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10233457/ (Full text)

Could vascular damage caused by massive inflammatory events underlie a relapse/recovery phenotype of ME/CFS and Long COVID?

Abstract:

I hypothesize that there is a relapse/recovery type of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and Long COVID in which a massive inflammatory event—like the inflammatory cascade prompted by the restoration of blood flow (reperfusion) to tissue that had been deprived of blood (ischemia) or an allergic or pseudoallergic reaction—causes substantial damage to blood vessels, launching a more severe phase of ME/CFS.
People with Ehlers-Danlos syndrome and other connective tissue disorders may be at particular risk of this phenotype due to having connective tissue (a key component of blood vessels) that is more easily and severely injured during inflammatory events and slower to heal, causing a much longer recovery.

Source: Tamara Carnac. Could vascular damage caused by massive inflammatory events underlie a relapse/recovery phenotype of ME/CFS and Long COVID? Patient-Generated Hypotheses Journal | Issue 1, May 2023. https://patientresearchcovid19.com/storage/2023/05/Patient-Generated-Hypotheses-Issue-1-May-2023.pdf#page=30 (Full text)

Chronic Fatigue Syndrome and Multiple Sclerosis have Reduced Craniospinal Compliance and Dilated Pressurized Bridging Cortical Veins: A Hypothesis Illustrated with Two Case Studies

Abstract:

Chronic fatigue syndrome (CFS) and multiple sclerosis (MS) share similarities regarding their epidemiology, symptomatology and craniospinal physiology. Indeed, the cardinal feature of CFS, fatigue, is also a major factor in the symptomatology of the majority of MS patients.

Recently, we have found that there is a significant reduction in the craniospinal compliance in MS which affects both the stiffness of the walls of the spinal canal and the walls of the cerebral venous system. This change in compliance brings about an alteration in the effectiveness of the pulse wave dampening in the craniospinal system. The result is an impedance mismatch between the cortical veins and their draining sinuses, leading to dilatation of these upstream veins.

We deduce this dilatation can only be brought about by an increase in the pressure gradient between the vein lumen and the subarachnoid space (i.e. the transmural pressure gradient). We hypothesise that given the similarities between MS and CFS, a similar mechanism underlies the physiology of CFS. We present two case studies to highlight the expected findings in CFS patients if this hypothesis were proven to be correct.

Source: Bateman, G.; Bateman, A. Chronic Fatigue Syndrome and Multiple Sclerosis have Reduced Craniospinal Compliance and Dilated Pressurized Bridging Cortical Veins: A Hypothesis Illustrated with Two Case Studies. Preprints.org 2023, 2023052264. https://doi.org/10.20944/preprints202305.2264.v1 https://www.preprints.org/manuscript/202305.2264/v1 (Full text available as PDF file)

Recovery and symptom trajectories up to two years after SARS-CoV-2 infection: population based, longitudinal cohort study

Abstract:

Objective: To evaluate longer term symptoms and health outcomes associated with post-covid-19 condition within a cohort of individuals with a SARS-CoV-2 infection.

Design: Population based, longitudinal cohort.

Setting: General population of canton of Zurich, Switzerland.

Participants: 1106 adults with a confirmed SARS-CoV-2 infection who were not vaccinated before infection and 628 adults who did not have an infection.

Main outcome measures: Trajectories of self-reported health status and covid-19 related symptoms between months six, 12, 18, and 24 after infection and excess risk of symptoms at six months after infection compared with individuals who had no infection.

Results: 22.9% (95% confidence interval 20.4% to 25.6%) of individuals infected with SARS-CoV-2 did not fully recover by six months. The proportion of individuals who had an infection who reported not having recovered decreased to 18.5% (16.2% to 21.1%) at 12 months and 17.2% (14.0% to 20.8%) at 24 months after infection. When assessing changes in self-reported health status, most participants had continued recovery (68.4% (63.8% to 72.6%)) or had an overall improvement (13.5% (10.6% to 17.2%)) over time. Yet, 5.2% (3.5% to 7.7%) had a worsening in health status and 4.4% (2.9% to 6.7%) had alternating periods of recovery and health impairment. The point prevalence and severity of covid-19 related symptoms also decreased over time, with 18.1% (14.8% to 21.9%) reporting symptoms at 24 months. 8.9% (6.5% to 11.2%) of participants reported symptoms at all four follow-up time points, while in 12.5% (9.8% to 15.9%) symptoms were alternatingly absent and present. Symptom prevalence was higher among individuals who were infected compared with those who were not at six months (adjusted risk difference 17.0% (11.5% to 22.4%)). Excess risk (adjusted risk difference) for individual symptoms among those infected ranged from 2% to 10%, with the highest excess risks observed for altered taste or smell (9.8% (7.7% to 11.8%)), post-exertional malaise (9.4% (6.1% to 12.7%)), fatigue (5.4% (1.2% to 9.5%)), dyspnoea (7.8% (5.2% to 10.4%)), and reduced concentration (8.3% (6.0% to 10.7%)) and memory (5.7% (3.5% to 7.9%)).

Conclusions: Up to 18% of individuals who were not vaccinated before infection had post-covid-19 condition up to two years after infection, with evidence of excess symptom risk compared with controls. Effective interventions are needed to reduce the burden of post-covid-19 condition. Use of multiple outcome measures and consideration of the expected rates of recovery and heterogeneity in symptom trajectories are important in the design and interpretation of clinical trials.

Registrations: ISRCTN18181860

Source: Ballouz T, Menges D, Anagnostopoulos A, Domenghino A, Aschmann HE, Frei A, Fehr JS, Puhan MA. Recovery and symptom trajectories up to two years after SARS-CoV-2 infection: population based, longitudinal cohort study. BMJ. 2023 May 31;381:e074425. doi: 10.1136/bmj-2022-074425. PMID: 37257891. https://www.bmj.com/content/381/bmj-2022-074425 (Full text)