A brief overview of SARS-CoV-2 infection and its management strategies: a recent update

Abstract:

The COVID-19 pandemic has become a global health crisis, inflicting substantial morbidity and mortality worldwide. A diverse range of symptoms, including fever, cough, dyspnea, and fatigue, characterizes COVID-19. A cytokine surge can exacerbate the disease’s severity. This phenomenon involves an increased immune response, marked by the excessive release of inflammatory cytokines like IL-6, IL-8, TNF-α, and IFNγ, leading to tissue damage and organ dysfunction.

Efforts to reduce the cytokine surge and its associated complications have garnered significant attention. Standardized management protocols have incorporated treatment strategies, with corticosteroids, chloroquine, and intravenous immunoglobulin taking the forefront. The recent therapeutic intervention has also assisted in novel strategies like repurposing existing medications and the utilization of in vitro drug screening methods to choose effective molecules against viral infections.

Beyond acute management, the significance of comprehensive post-COVID-19 management strategies, like remedial measures including nutritional guidance, multidisciplinary care, and follow-up, has become increasingly evident. As the understanding of COVID-19 pathogenesis deepens, it is becoming increasingly evident that a tailored approach to therapy is imperative.

This review focuses on effective treatment measures aimed at mitigating COVID-19 severity and highlights the significance of comprehensive COVID-19 management strategies that show promise in the battle against COVID-19.

Source: Das A, Pathak S, Premkumar M, Sarpparajan CV, Balaji ER, Duttaroy AK, Banerjee A. A brief overview of SARS-CoV-2 infection and its management strategies: a recent update. Mol Cell Biochem. 2023 Sep 24. doi: 10.1007/s11010-023-04848-3. Epub ahead of print. PMID: 37742314. https://link.springer.com/article/10.1007/s11010-023-04848-3 (Full text)

Proximal immune-epithelial progenitor interactions drive chronic tissue sequelae post COVID-19

Abstract:

The long-term health effects of SARS-CoV-2, termed Post-Acute Sequelae of COVID-19 (PASC), are quickly evolving into a major public health concern, but the underlying cellular and molecular etiology remain poorly defined. There is growing evidence that PASC is linked to abnormal immune responses and/or poor organ recovery post-infection. However, the exact processes linking non-resolving inflammation, impaired tissue repair, and PASC are still unclear.

In this report, we utilized a cohort of respiratory PASC patients with viral infection-mediated pulmonary fibrosis and a clinically relevant mouse model of post-viral lung sequelae to investigate the pathophysiology of respiratory PASC. Using a combination of imaging and spatial transcriptomics, we identified dysregulated proximal interactions between immune cells and epithelial progenitors unique to respiratory PASC but not acute COVID-19 or idiopathic pulmonary fibrosis (IPF). Specifically, we found a central role for lung-resident CD8+ T cell-macrophage interactions in maintaining Krt8hi transitional and ectopic Krt5+ basal cell progenitors, and the development of fibrotic sequelae after acute viral pneumonia.

Mechanistically, CD8+ T cell derived IFN-γ and TNF stimulated lung macrophages to chronically release IL-1β, resulting in the abnormal accumulation of dysplastic epithelial progenitors in fibrotic areas. Notably, therapeutic neutralization of IFN-γ and TNF, or IL-1β after the resolution of acute infection resulted in markedly improved alveolar regeneration and restoration of pulmonary function.

Together, our findings implicate a dysregulated immune-epithelial progenitor niche in driving respiratory PASC and identify potential therapeutic targets to dampen chronic pulmonary sequelae post respiratory viral infections including SARS-CoV-2.

Source: Narasimhan H, Cheon IS, Qian W, Hu S, Parimon T, Li C, Goplen N, Wu Y, Wei X, Son YM, Fink E, Santos G, Tang J, Yao C, Muehling L, Canderan G, Kadl A, Cannon A, Pramoonjago P, Shim YM, Woodfolk J, Zang C, Chen P, Sun J. Proximal immune-epithelial progenitor interactions drive chronic tissue sequelae post COVID-19. bioRxiv [Preprint]. 2023 Sep 14:2023.09.13.557622. doi: 10.1101/2023.09.13.557622. PMID: 37745354; PMCID: PMC10515929. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10515929/ (Full text)

Increased SARS-CoV-2 reactive low avidity T cells producing inflammatory cytokines in pediatric post-acute COVID-19 sequelae (PASC)

Abstract:

Background: A proportion of the convalescent SARS-CoV-2 pediatric population presents nonspecific symptoms, mental health problems and a reduction in quality of life similar to myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and long COVID-19 symptomatic. However, data regarding its clinical manifestation and immune mechanisms are currently scarce.

Methods: In this study, we perform a comprehensive clinical and immunological profiling of 17 convalescent COVID-19 children with post-acute COVID-19 sequelae (PASC) manifestation and 13 convalescent children without PASC manifestation. A detailed medical history, blood and instrumental tests and physical examination were obtained from all patients. SARSCoV-2 reactive T cell response was analyzed via multiparametric flowcytometry and the humoral immunity was addressed via pseudovirus neutralization and ELISA assay.

Results: The most common PASC symptoms were shortness of breath/exercise intolerance, paresthesia, smell/taste disturbance, chest pain, dyspnea, headache and lack of concentration. Blood count and clinical chemistry showed no statistical differences among the study groups. We detected higher frequencies of spike (S) reactive CD4+ and CD8+ T cells among the PASC study group, characterized by TNFα and IFNγ production and low functional avidity. CRP levels are positively correlated with IFNγ producing reactive CD8+ T cells.

Conclusions: Our data might indicate a possible involvement of a persistent cellular inflammatory response triggered by SARS-CoV-2 in the development of the observed sequelae in pediatric PASC. These results may have implications on future therapeutic and prevention strategies.

Source: Krystallenia Paniskaki, et al. Increased SARS-CoV-2 reactive low avidity T cells producing inflammatory cytokines in pediatric post-acute COVID-19 sequelae (PASC) https://d197for5662m48.cloudfront.net/documents/publicationstatus/144335/preprint_pdf/a855de5e766f9457795050e56413075a.pdf (Full text)

Circulating Reelin promotes inflammation and modulates disease activity in acute and long COVID-19 cases

Abstract:

Thromboembolic complications and excessive inflammation are frequent in severe COVID-19, potentially leading to long COVID. In non-COVID studies, we and others demonstrated that circulating Reelin promotes leukocyte infiltration and thrombosis. Thus, we hypothesized that Reelin participates in endothelial dysfunction and hyperinflammation during COVID-19.

We showed that Reelin was increased in COVID-19 patients and correlated with the disease activity. In the severe COVID-19 group, we observed a hyperinflammatory state, as judged by increased concentration of cytokines (IL-1α, IL-4, IL-6, IL-10 and IL-17A), chemokines (IP-10 and MIP-1β), and adhesion markers (E-selectin and ICAM-1).

Reelin level was correlated with IL-1α, IL-4, IP-10, MIP-1β, and ICAM-1, suggesting a specific role for Reelin in COVID-19 progression. Furthermore, Reelin and all of the inflammatory markers aforementioned returned to normal in a long COVID cohort, showing that the hyperinflammatory state was resolved. Finally, we tested Reelin inhibition with the anti-Reelin antibody CR-50 in hACE2 transgenic mice infected with SARS-CoV-2. CR-50 prophylactic treatment decreased mortality and disease severity in this model.

These results demonstrate a direct proinflammatory function for Reelin in COVID-19 and identify it as a drug target. This work opens translational clinical applications in severe SARS-CoV-2 infection and beyond in auto-inflammatory diseases.

Source: Calvier L, Drelich A, Hsu J, Tseng CT, Mina Y, Nath A, Kounnas MZ, Herz J. Circulating Reelin promotes inflammation and modulates disease activity in acute and long COVID-19 cases. Front Immunol. 2023 Jun 27;14:1185748. doi: 10.3389/fimmu.2023.1185748. PMID: 37441066; PMCID: PMC10333573. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10333573/ (Full text)

Correlation between Hepatocyte Growth Factor (HGF) with D-Dimer and Interleukin-6 as Prognostic Markers of Coagulation and Inflammation in Long COVID-19 Survivors

Abstract:

In general, an individual who experiences the symptoms of Severe Acute Respiratory Syndrome Coronavirus 2 or SARS-CoV-2 infection is declared as recovered after 2 weeks. However, approximately 10–20% of these survivors have been reported to encounter long-term health problems, defined as ‘long COVID-19’, e.g., blood coagulation which leads to stroke with an estimated incidence of 3%, and pulmonary embolism with 5% incidence.
At the time of infection, the immune response produces pro-inflammatory cytokines that stimulate stromal cells to produce pro-hepatocyte growth factor (pro-HGF) and eventually is activated into hepatocyte growth factor (HGF), which helps the coagulation process in endothelial and epithelial cells. HGF is a marker that appears as an inflammatory response that leads to coagulation.
Currently, there is no information on the effect of SARS-CoV-2 infection on serum HGF concentrations as a marker of the prognosis of coagulation in long COVID-19 survivors. This review discusses the pathophysiology between COVID-19 and HGF, IL-6, and D-dimer.
Source: Zaira B, Yulianti T, Levita J. Correlation between Hepatocyte Growth Factor (HGF) with D-Dimer and Interleukin-6 as Prognostic Markers of Coagulation and Inflammation in Long COVID-19 Survivors. Current Issues in Molecular Biology. 2023; 45(7):5725-5740. https://doi.org/10.3390/cimb45070361 https://www.mdpi.com/1467-3045/45/7/361 (Full text)

A Thesis on Immune Differences in Chronic Fatigue Syndrome, Fibromyalgia and Healthy Controls

Abstract:

Background: Chronic Fatigue Syndrome (CFS) and Fibromyalgia (FM) are debilitating disorders that significantly affect the daily lives of those suffering from them, as well as their loved ones. Both conditions have overlapping clinical features that resemble inflammatory disorders, and overlapping symptoms, such as depression, suggest central nervous system (CNS) involvement. The role of the immune system’s soluble messengers in the pathogenesis of CFS and FM has been under investigation, but so far the results are inconclusive. In addition, there is growing evidence that the kynurenine pathway is involved in the pathology of diseases related to the CNS, yet the role of each metabolite is not clear. The relationship between kynurenine metabolism and CFS and FM has not been extensively explored. Few studies have simultaneously examined the immunological status in both CFS and FM, making this thesis the first to comprehensively evaluate the potential distinct immunological differences between the two disorders.

Objective: The objective of this study was to compare the CFS and FM with healthy controls, regarding the levels of several soluble blood markers related to the immune system. The markers chosen were:

  • The inflammatory marker high-sensitive CRP (hsCRP)
  • The following cytokines and chemokines: Interferon (IFN)-γ, Interleukin (IL)-1β, IL1ra, IL-4, IL-6, IL-8, IL-10, IL-17, Interferon gamma-induced protein (IP)-10, Monocyte Chemoattractant Protein (MCP)-1, Transforming Growth Factor (TGF)-β1, TGF-β2, TGF-β3 and Tumour Necrosis Factor (TNF)-α
  • The metabolites and their ratios of the kynurenine pathway: Tryptophan (Try), kynurenine (Kyn), kynurenic acid (KA), 3-hydroxykykynurenine (HK), anthranilic acid (AA), xanthurenic acid (XA), 3-hydroxyanthranilic acid (HAA), quinolinic acid (QA) and picolinic acid (Pic).

Method: The population consisted of three groups: CFS patients (n = 49), FM patients (n = 58), and healthy controls (n = 54). All participants were females aged 18–60. Patients were recruited from a specialised university hospital clinic and controls were recruited by advertisement among the staff and students at the hospital and university.

Plasma levels of hsCRP were analysed at the hospital. The cytokines and chemokines IFN-γ, IL-1β, IL-1ra, xii IL-4, IL-6, IL-8, IL-10, IL-17, IP-10, MCP-1, TGF-β1, TGF-β2, TGF-β3, and TNF-α were analysed by multiplex. Kynurenine metabolites were analysed by LC-MS/MS.

Linear regression models of log-transformed data for hsCRP and the kynurenine metabolites were conducted for comparison of the three groups CFS, FM and controls. The Kruskal-Wallis test was used to analyse differences of cytokines between the three groups. Main findings were controlled for age, body mass index (BMI), and symptoms of anxiety and depression.

Results: hsCRP levels were significantly higher for both the CFS and FM groups compared to healthy controls when adjusting for age and BMI (p = .006). There was no difference between the two patient groups. Level of hsCRP was affected by BMI (p < .001) but not age.

MCP-1 was significantly increased in both patient groups compared to healthy controls (p < .001). IL-1β, Il-4, IL-6, TNF-α, TGF-β1, TGF-β2, TGF-β3 (all p < .001), IL-10 (p = .003) and IL17 (p = .002) all were significantly lower in the patient groups compared to healthy controls. IFN-γ was significantly lower in the FM group (p < .001). For IL-8, IP-10 and IL1ra there were no significant difference.

QA differed between CFS and FM patients (p = .036) and was related to higher levels of BMI (p = .002). The KA/QA ratio was lower for CFS patients compared to healthy controls (p = .016). The KA/HK ratio was lower for FM patients compared to healthy controls, and this lower ratio was associated with increased symptoms of pain (p = .002). The kynurenine aminotransferase II (KAT II) enzymatic activity given by XA/HK was lower for FM patients compared to healthy controls (p = .013). In addition, BMI was negatively associated with enhanced KAT II enzymatic activity (p = .039).

Symptoms of anxiety and depression were not associated with any of the immune markers studied.

Conclusion: In our material hsCRP and MCP-1 are increased in patients both with CFS and with FM, while several other cytokines are either similar or significantly lower in patients than controls. Our study also indicates associations between kynurenine metabolism and CFS and FM. Kynurenine also is associated with single symptoms such as fatigue and pain. Forthcoming studies indicating interactions and causative effects, or restoration of the inflammatory status, may place cytokines and kynurenine metabolites as a target for treatment as well as prevention of these conditions in the future.

Source: Groven, Nina. A Thesis on Immune Differences in Chronic Fatigue Syndrome, Fibromyalgia and Healthy Controls. PhD Thesis [Norwegian University of Science and Technology] https://ntnuopen.ntnu.no/ntnu-xmlui/handle/11250/3072207 (Full text available as PDF file)

Low avidity circulating SARS-CoV-2 reactive CD8+ T cells with proinflammatory TEMRA phenotype are associated with post-acute sequelae of COVID-19

Abstract:

The role of adaptive SARS-CoV-2 specific immunity in post-acute sequelae of COVID-19 (PASC) is not well explored, although a growing population of convalescent COVID-19 patients with manifestation of PASC is observed.

We analyzed the SARS-CoV-2-specific immune response, via pseudovirus neutralizing assay and multiparametric flow cytometry in 40 post-acute sequelae of COVID-19 patients with non-specific PASC manifestation and 15 COVID-19 convalescent healthy donors. Although frequencies of SARS-CoV-2-reactive CD4+ T cells were similar between the studied cohorts, a stronger SARS-CoV-2 reactive CD8+ T cell response, characterized by IFNγ production and predominant TEMRA phenotype but low functional TCR avidity was detected in PASC patients compared to controls. Of interest, high avidity SARS-CoV-2-reactive CD4+ and CD8+ T cells were comparable between the groups demonstrating sufficient cellular antiviral response in PASC. In line with the cellular immunity, neutralizing capacity in PASC patients was not inferior compared to controls.

In conclusion, our data suggest that PASC may be driven by an inflammatory response triggered by an expanded population of low avidity SARS-CoV-2 reactive pro-inflammatory CD8+ T cells. These pro-inflammatory T cells with TEMRA phenotype are known to be activated by a low or even without TCR stimulation and lead to a tissue damage. Further studies including animal models are required for a better understanding of underlying immunopathogensis.

Summary: A CD8+ driven persistent inflammatory response triggered by SARS-CoV-2 may be responsible for the observed sequelae in PASC patients.

Source: Paniskaki K, Konik MJ, Anft M, Heidecke H, Meister TL, Pfaender S, Krawczyk A, Zettler M, Jäger J, Gaeckler A, Dolff S, Westhoff TH, Rohn H, Stervbo U, Scheibenbogen C, Witzke O, Babel N. Low avidity circulating SARS-CoV-2 reactive CD8+ T cells with proinflammatory TEMRA phenotype are associated with post-acute sequelae of COVID-19. Front Microbiol. 2023 Jun 2;14:1196721. doi: 10.3389/fmicb.2023.1196721. PMID: 37333646; PMCID: PMC10272838. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10272838/ (Full text)

Prolonged T-cell activation and long COVID symptoms independently associate with severe COVID-19 at 3 months

Abstract:

COVID-19 causes immune perturbations which may persist long-term, and patients frequently report ongoing symptoms for months after recovery. We assessed immune activation at 3-12 months post hospital admission in 187 samples from 63 patients with mild, moderate or severe disease and investigated whether it associates with long COVID.

At 3 months, patients with severe disease displayed persistent activation of CD4+ and CD8+ T-cells, based on expression of HLA-DR, CD38, Ki67 and granzyme B, and elevated plasma levels of IL-4, IL-7, IL-17 and TNF-α compared to mild and/or moderate patients. Plasma from severe patients at 3 months caused T-cells from healthy donors to upregulate IL-15Rα, suggesting that plasma factors in severe patients may increase T-cell responsiveness to IL-15-driven bystander activation.

Patients with severe disease reported a higher number of long COVID symptoms which did not however, correlate with cellular immune activation/pro-inflammatory cytokines after adjusting for age, sex and disease severity. Our data suggests that long COVID and persistent immune activation may correlate independently with severe disease.

Source: Marianna Santopaolo, Michaela Gregorova, Fergus Hamilton, David Arnold, Anna Long, Aurora Lacey, Alice Halliday, Holly Baum, Kristy Hamilton, Rachel Milligan, Elizabeth Oliver, Olivia Pearce, Lea Knezevic, Begonia Morales Aza, Alice Milne, Emily Milodowski, Eben Jones, Rajeka Lazarus, Anu Goenka, Adam Finn, Nicholas Maskell, Andrew D Davidson, Kathleen Gillespie, Linda Wooldridge, Laura Rivino (2023) Prolonged T-cell activation and long COVID symptoms independently associate with severe COVID-19 at 3 months eLife 12:e85009 https://doi.org/10.7554/eLife.85009 https://elifesciences.org/articles/85009

Persistent serum protein signatures define an inflammatory subcategory of long COVID

Abstract:

Long COVID or post-acute sequelae of SARS-CoV-2 (PASC) is a clinical syndrome featuring diverse symptoms that can persist for months following acute SARS-CoV-2 infection. The aetiologies may include persistent inflammation, unresolved tissue damage or delayed clearance of viral protein or RNA, but the biological differences they represent are not fully understood. Here we evaluate the serum proteome in samples, longitudinally collected from 55 PASC individuals with symptoms lasting ≥60 days after onset of acute infection, in comparison to samples from symptomatically recovered SARS-CoV-2 infected and uninfected individuals.

Our analysis indicates heterogeneity in PASC and identified subsets with distinct signatures of persistent inflammation. Type II interferon signaling and canonical NF-κB signaling (particularly associated with TNF), appear to be the most differentially enriched signaling pathways, distinguishing a group of patients characterized also by a persistent neutrophil activation signature.

These findings help to clarify biological diversity within PASC, identify participants with molecular evidence of persistent inflammation, and highlight dominant pathways that may have diagnostic or therapeutic relevance, including a protein panel that we propose as having diagnostic utility for differentiating inflammatory and non-inflammatory PASC.

Source: Talla, A., Vasaikar, S.V., Szeto, G.L. et al. Persistent serum protein signatures define an inflammatory subcategory of long COVID. Nat Commun 14, 3417 (2023). https://doi.org/10.1038/s41467-023-38682-4 https://www.nature.com/articles/s41467-023-38682-4 (Full text)

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