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The coronavirus SARS-CoV-2 was detected in isolates of pneumonia patients in January 2020. The virus cannot multiply extracellularly but requires access to the cells of a host organism. SARS-CoV-2 uses angiotensin-converting enzyme 2 (ACE2) as a receptor, to which it docks with its spikes. ACE2 belongs to the renin angiotensin system (RAS), whose inhibitors have been used for years against high blood pressure. Renin is an endopeptidase that is predominantly formed in the juxtaglomerular apparatus of the kidney and cleaves the decapeptide angiotensin I (Ang I) from angiotensinogen. Through the angiotensin-converting enzyme (ACE), another 2 C-terminal amino acids are removed from Ang I, so that finally the active octapeptide angiotensin II (Ang II) is formed. The biological effect of Ang II via the angiotensin II receptor subtype 1 (AT1-R) consists of vasoconstriction, fibrosis, proliferation, inflammation, and thrombosis formation. ACE2 is a peptidase that is a homolog of ACE. ACE2 is predominantly expressed by pulmonary alveolar epithelial cells in humans and has been detected in arterial and venous endothelial cells. In contrast to the dicarboxy-peptidase ACE, ACE2 is a monocarboxypeptidase that cleaves only one amino acid from the C-terminal end of the peptides. ACE2 can hydrolyze the nonapeptide Ang-(1-9) from the decapeptide Ang I and the heptapeptide Ang-(1-7) from the octapeptide Ang II. Ang-(1-7) acts predominantly antagonistically (vasodilatory, anti-fibrotic, anti-proliferative, anti-inflammatory, anti-thrombogenetically) via the G protein-coupled Mas receptor to the AT1-R-mediated effects of Ang II. In the pathogenesis of COVID-19 infection, it is therefore assumed that there is an imbalance due to overstimulation of the AT1 receptor in conjunction with a weakening of the biological effects of the Mas receptor.Copyright © 2022 Dustri-Verlag Dr. K. Feistle.
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Spontaneous pneumomediastinum, pneumothorax, pneumoperitoneum, and soft tissue emphysema have been recently described in several sources as possible complications in patients with severe COVID-19 and lung damage. This clinical case is dedicated to demonstrarte the development of these lesions in 3 male patients with comorbid conditions. The putative pathophysiological mechanism of these complications is air leakage due to extensive diffuse alveolar damage followed by rupture of the alveoli. All presented patients had a favorable outcome of the disease without lethal cases, their laboratory data and clinical dynamics were described. It should be noted that such conditions are not rare complications of COVID-19, and are observed mainly in male patients with severe form of the disease and the presence of comorbid conditions. Such complications are associated with long hospitalization and a severe prognosis. In some cases, with a mild course of the disease and positive dynamics in a decrease of the percentage of pulmonary lesions, the outcome is favorable, not requiring additional invasive interventions.Copyright © 2022 Medical Visualization. All rights reserved.
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Objective: Although the neurological and olfactory symptoms of coronavirus disease 2019 have been identified, the neurotropic properties of the causative virus, severe acute respiratory syndrome-associated coronavirus 2 (SARS-CoV-2), remain unknown. We sought to identify the susceptible cell types and potential routes of SARS-CoV-2 entry into the central nervous system, olfactory system, and respiratory system. Method(s): We collected single-cell RNA data from normal brain and nasal epithelium specimens, along with bronchial, tracheal, and lung specimens in public datasets. The susceptible cell types that express SARS-CoV-2 entry genes were identified using single-cell RNA sequencing and the expression of the key genes at protein levels was verified by immunohistochemistry. We compared the coexpression patterns of the entry receptor angiotensin-converting enzyme 2 (ACE2) and the spike protein priming enzyme transmembrane serine protease (TMPRSS)/cathepsin L among the specimens. Result(s): The SARS-CoV-2 entry receptor ACE2 and the spike protein priming enzyme TMPRSS/cathepsin L were coexpressed by pericytes in brain tissue;this coexpression was confirmed by immunohistochemistry. In the nasal epithelium, ciliated cells and sustentacular cells exhibited strong coexpression of ACE2 and TMPRSS. Neurons and glia in the brain and nasal epithelium did not exhibit coexpression of ACE2 and TMPRSS. However, coexpression was present in ciliated cells, vascular smooth muscle cells, and fibroblasts in tracheal tissue;ciliated cells and goblet cells in bronchial tissue;and alveolar epithelium type 1 cells, AT2 cells, and ciliated cells in lung tissue. Conclusion(s): Neurological symptoms in patients with coronavirus disease 2019 could be associated with SARS-CoV-2 invasion across the blood-brain barrier via pericytes. Additionally, SARS-CoV-2-induced olfactory disorders could be the result of localized cell damage in the nasal epithelium.Copyright © Wolters Kluwer Health, Inc. All rights reserved.
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Introduction: SARS-CoV-2 is responsible for the current global pandemic. SARS-CoV-2 infection underlies the novel viral condition coronavirus disease 2019 (COVID-19). COVID-19 causes significant pulmonary sequelae contributing to serious morbidities. The pathogenesis of COVID-19 is complex with a multitude of factors leading to varying levels of injury numerous extrapulmonary organs. This review of 124 published articles documenting COVID- 19 autopsies included 1,142 patients. Method(s): A PubMed search was conducted for COVID-19 autopsy reports published before March 2021 utilizing the query COVID-19 Autopsy. There was no restriction regarding age, sex, or ethnicity of the patients. Duplicate cases were excluded. Findings were listed by organ system from articles that met selection criteria. Result(s): Pulmonary pathology (72% of articles;866/1142 patients): diffuse alveolar damage (563/866), alveolar edema (251/866), hyaline membrane formation (234/866), type II pneumocyte hyperplasia (165/866), alveolar hemorrhage (164/866), and lymphocytic infiltrate (87/866). Vascular pathology (41% of articles;771/1142 patients): vascular thrombi (439/771)-microvascular predominance (294/439)-and inflammatory cell infiltrates (116/771). Cardiac pathology (41% of articles;502/1142 patients): cardiac inflammation (186/502), fibrosis (131/502), cardiomegaly (100/502), hypertrophy (100/502), and dilation (35/502). Hepatic pathology (33% of articles;407/1142 patients): steatosis (106/402) and congestion (102/402). Renal pathology (30% of articles;427/1142 patients): renal arteries arteriosclerosis (111/427), sepsis-associated acute kidney injury (81/427) and acute tubular necrosis (77/427). Conclusion(s): This review revealed anticipated pulmonary pathology, along with significant extrapulmonary involvement secondary to COVID-19, indicating widespread viral tropism throughout the human body. These diverse effects require additional comprehensive longitudinal studies to characterize short-term and long-term COVID-19 sequelae and inform COVID-19 treatment.
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Autoimmune pulmonary alveolar proteinosis (PAP) is a rare disease, especially in pediatrics, but important to consider, as it may avoid unnecessary and/or invasive investigations and delayed diagnosis. This case report highlights an adolescent girl with rapid onset dyspnea but an unremarkable physical exam and initial testing. However, due to a high index of suspicion, a chest computed tomography (CT) scan was done, revealing a "crazy paving" pattern, which then prompted expedited assessment. This finding, however, is not as specific as often discussed and has a broad differential diagnosis, which will be reviewed in detail as part of this case. Furthermore, this report demonstrates a diagnostic approach for PAP that avoids lung biopsy, previously considered to be required for diagnosis of PAP, but is increasingly becoming unnecessary with more advanced blood tests and understanding of their sensitivity and specificity. Additionally, management strategies for PAP will be briefly discussed.Copyright © 2022 Canadian Thoracic Society.
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The development of coronavirus infection outbreak into a pandemic, coupled with the lack of effective COVID-19 therapies, is a challenge for the entire pharmaceutical industry. This study aimed to assess the treatment and preventive efficacy of the amino acid-peptide complex (APC) in male Syrian hamsters infected with SARSCoV-2 (intranasal administration of 26 mul of the virus culture, titer of 4 x 104 TCD50/ml). In a modeled COVID-19 case, APC administered for treatment and preventive purposes reduced lung damage. Compared to the positive control group, test group had the lung weight factor 15.2% smaller (trend), which indicates a less pronounced edema. Microscopic examination revealed no alveolar edema, atypical hypertrophied forms of type II alveolocytes, pulmonary parenchyma fibrinization. The macrophage reaction intensified, which is probably a result of the APC-induced activation of regenerative processes in the lung tissues. Spleens of the animals that received APC for therapeutic and preventive purposes were less engorged and had fewer hemorrhages. The decrease of body weight of the test animals that received APC for treatment and prevention was insignificant (p < 0.05), which indicates a less severe course of COVID-19. Administered following a purely therapeutic protocol, APC proved ineffective against SARS-CoV-2 post-infection. Thus, APC-based drug used as a therapeutic and preventive agent reduces pulmonary edema and makes morphological signs of lung tissue damage less pronounced in male Syrian hamsters infected with SARS-CoV-2.Copyright © Extreme Medicine.All right reserved.
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The series of autopsies reported since the beginning of the pandemic have highlighted several patterns of lung damage, both isolated and combined. The factors influencing the occurrence of these different tissue responses to viral aggression by SARS-CoV-2 have not yet been determined. In asymptomatic patients or patients with respiratory symptoms who were not ventilated, lymphocyte pneumonia associated with type II pneumocyte atypical hyperplasia and a few hyaline membranes or focal lesions of acute fibrinous pneumonia have been observed. In critically ill patients, the most frequent pattern is diffuse alveolar damage with interstitial lymphoid infiltration, type II pneumocyte atypia and, very often, capillary or arteriolar microthromboses and/or endothelitis. The precise description of these lesions, which is becoming more and more consensual, makes it possible to understand the favourable effects of corticosteroid therapy in seriously ill patients and the evolution under ventilation towards fibrosis.Copyright © ERS 2021.
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The novel SARS-CoV-2 virus known to cause the COVID-19 outbreak has resulted in a global healthcare crisis that has persisted the past 3 years. Thus, understanding the mechanisms underlying this disease are vital at this time. While there are issues of research infrastructure to handle the virus and because of the refractoriness of rodents to this disease, the availability of these tools is still limited. The cytokine storm and fatality presented in patients with severe COVID-19 can be mimicked with Staphylococcal enterotoxin B (SEB)-induced Acute Respiratory Distress Syndrome (ARDS). Within ~7 days, the survival rate drops to 0% for C3H/HeJ mice exposed to a dual dose of SEB. In this study, we administered cannabidiol (CBD) intraperitoneally for 3 days pre- and post-SEB dosing and found that the clinical outcomes improved significantly. Initial evaluation of scRNASeq data from lungs comparing naive to SEB-induced ARDS mice illustrated an increase in infiltrating immune cells, and a loss in pulmonary epithelial cells in the latter group. When evaluating the effect of CBD treatment on SEB-induced ARDS, we were able to demonstrate that CBD reduced the macrophage population. To characterize the mechanism by which CBD treatment ameliorated the inflammatory response, we found that CBD treated mice had significant reduction in infiltrating immune cells and alveolar thickening. This same histology and infiltration is presented in ARDS. MicroRNA expression analysis showed a significant increase in the expression mmu-miR-298-5p and mmu-miR- 566 with CBD treatment. Ingenuity Pathway Analysis (IPA) indicated that the dysregulated miRNAs were also implicated in pathways associated with macrophage activation, respiratory disease and inflammation, interferon stimulated genes, as well as genes which have been upregulated in the disease state of this model. These targets include but are not limited to Cebpb, Efhd2, Stat3, Socs3, Cxcl5, Gbp2, and Birc3. This finding offers insights for the development of preventive and therapeutic strategies in the treatment of ARDS, including that induced in COVID-19. Supported by NIH grants P01AT003961, P20GM103641, R01ES003961, R01AI129788, R01AI123947, R01AI160896 to MN and PSN and K99GM147910 to KW.Copyright © 2023 The American Society for Biochemistry and Molecular Biology, Inc.
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COVID-19 is a highly transmissible disease with severe course especially in patients with nephrogenic hypertensive disease and chronic kidney disease due to a higher incidence of all-type infections than in the general population. The aim of the study is to describe a clinical case of SARS-CoV-2 infection complicated by nephrogenic pulmonary edema and COVID-associated pneumonitis, alveolitis. Description of the case. Patient K.S., born in 1975, was hospitalized 24 hours after symptom onset at emergency hospital due to complaints of increased blood pressure up to 180-200/110-120 mm Hg, temperature up to 38.7degreeC, dry cough, feeling of heaviness in the chest, change in urine color. PCR smear for SARS-CoV-2 was positive. Computed tomography revealed a pattern of bilateral COVID-associated pneumonitis, alveolitis, with 75% involvement. The electrocardiogram revealed signs of left ventricular myocardial hypertrophy. Ultrasound examination showed numerous cysts in the kidneys. Urinalysis at admission: leukocytes - 499, erythrocytes - 386. Glomerular filtration rate (CKD-EPI: 29 ml/min/1.73 m2) and corresponds to stage IV of chronic kidney disease. Coagulogram: fibrinogen: 32.3 (1.6-4.0) g/l, D-dimer: 663 (0-250). Despite the treatment, the patient's condition worsened, the phenomena of cardiopulmonary and renal insufficiency increased, which led to a fatal outcome. During a virological study of sectional material: SARS-CoV-2 coronavirus RNA was found in the lung and kidneys. Signs of bilateral COVID-associated pneumonitis, alveolitis with diffuse cellular infiltrates in combination with changes in the alveolar apparatus, signs of pulmonary edema were revealed. Heart-related signs - swelling of the interstitium, fragmented muscle fibers, some of them hypertrophied, a wave-like deformation of cardiomyocytes, blurring of the transverse striation. Arteries with thickened sclerosed walls. In the kidneys - diffuse damage to the proximal tubules of the nephron with areas of cortical and proximal necronephrosis, areas of fibrinoid swelling. Conclusion. The cause of death of a 45-year-old patient was a severe course of bilateral COVID-associated pneumonitis, alveolitis, which contributed to the development of renal medullary hypoxia and type 1 cardiorenal syndrome, which led to early nephrogenic pulmonary edema.Copyright © 2023 Saint Petersburg Pasteur Institute. All rights reserved.
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Study objective. It has been shown that human common viruses are new target genes for host cell dioxin receptor transcriptional (AhR-ARNT) complex initially proven to up-regulate mammalian genes containing dioxin-response elements (DRE) in the promoters [doi:10.1016/j.ijid.2012.05.265]. Initially, transactivation of HIV-1 and HBV by 2,3,7,8-tetrachlodibenzop- dioxin (TCDD) at low nanomolar range was demonstrated [doi:10.3109/00498259309057034]. Noteworthy, transactivation of human cytomegalovirus (CMV) was shown with 0.3 ppt dioxin, i.e. lower than its current background level in the general population (~3.0 ppt). Recently, reactivation of CMV infection was found to influence worse clinical outcome following SARS-CoV-2 infection (doi: 10.1186/s12979-020- 00185-x). Other findings showed that CMV and herpes simplex virus 1 (HSV-1) reactivation were observed in immunocompetent patients with COVID-19 acute respiratory distress syndrome (ARDS) (doi.org/10.1186/s13054-020-03252-3). Addressing occurrence of Herpesviridae reactivation in severe COVID-19 patients, and still unspecified real triggers of CMV and HSV-1 reactivations, we tested TCDD, which current body burden (DBB) ranges from 20 pg/g (TEQ in fat) in general population to 100 pg/g in older people. Methods. In Silico quantitation of active DRE in promoters of viral genes. Virus DNA hybridization assay. Clinical and epidemiological analyses. Results and Discussion. In this study, a computational search for DRE in CMV and HSV-1 genes was performed by SITECON, a tool recognizing potentially active transcriptional factor binding sites. In silico analysis revealed in regulatory region of CMV IE genes from 5 to 10 DRE, and from 6 to 8 DRE in regulatory region of HSV-1 IE genes.We established that a low picomolar TCDD can trigger up-regulation of CMV and HSV-1 genes via AhR:Arnt transcription factor in macrophage(doi.org/10.1016/ j.ijid.2012.05.265) and glial human cell lines (doi.org/10.1016/j. jalz.2016.06.1268), respectively. In fact, viral reactivation may be triggered in COVID-19 ARDS patients by higher pulmonary TCDD concentrations, because "lipid storm" within lungs of severe COVID-19 patients has been recently reported (doi.org/ 10.1101/2020.12.04.20242115). TCDD is known as the most potent xenobiotic, which bioaccumulates and has estimation half-life in humans of up to 10 yr. Due to hydrophobic character (Log P octanol/water: 7.05), TCDD partitions into inflammatory lipids in lung tissue thus augmenting its local concentration. Population-based epidemiological data on SARS-CoV-2 first wave of pandemic revealed high level of CMV seropositivity and cumulative mortality rate 4.5 times in Lombardi region of Italy, where after Seveso industrial accident TCDD plasma level in pre-exposed subjects is 15 times the level in rest of Italy (doi. org/10.3389/fpubh.2020.620416). Also, Arctic Native (AN) peoples consume dioxin-contaminated fat in seafood and have TCDD DBB, i.e. 7 times that in general population. To the point of this paper, their COVID-19 mortality is 2.2 times of that among non-AN Alaskans (doi: 10.15585/mmwr.mm6949a3). Conclusion(s): TCDD in the picomolar range may trigger CMV expression in lung cells and commit virus to the lytic cycle, which can be applied to reactivation of Herpesviridae infection in immunocompetent patients with COVID-19 ARDS syndrome.Copyright © 2023 The American Society for Biochemistry and Molecular Biology, Inc.
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Background: The continuous evolution of SARS-CoV-2 in the diverse immune landscape (natural, vaccine, hybrid) is giving rise to novel immune escape mutations. So far, the resulting new variants (BA.1, BA.2, BA.2.12.1) were observed to cause mild infections, however, BA.5 infections are associated with an increased risk of hospitalization.1 Therefore it is essential to investigate the pathogenesis of BA.5. Method(s): Here we compared the pathogenicity of Pre-Omicron (B.1.351) and Omicron (BA.1, BA.2.12.1, and BA.5) variants in wild-type C57BL/6J mice and K18-hACE2 mice. The virus replication kinetics was also studied in human Calu3, pulmonary alveolar type 2 (AT2) cells, and airway organoids (HAO). Cell-to-cell spread of virus was measured by syncytia formation assay and immunohistochemistry (IHC) of infected lungs. Result(s): In the results, infection in C57BL/6J mice showed severe weight loss ( >15%) for B.1.351 infected mice and moderate ( >5%) for BA.5 infected. C57BL/6J mice showed higher virus replication of B.1.351 followed by BA.5, BA.1, and BA.2.12.1. At the peak of virus replication (2 days) plaque-forming units from lung extract of BA.5 infected mice were two, and three logs higher compared to BA.1 and BA.2.12.1 respectively. BA.5 infection was lethal to 80% of infected K18-hACE2 mice, whereas the mice looked normal after infection with BA.1 and BA.2.12.1. BA.5 infected mice showed high virus replication in brain tissue. Surprisingly the syncytia formation assay and IHC for BA.5 was comparable to that of B.1.351, indicating the higher cell-to-cell spread of BA.5 and B.1.351 compared to BA.1 and BA.2.12.1, which is one of the measures of pathogenicity. Calu3 and HAO showed the same trend of virus replication as was observed in-vivo experiments however AT2 cells were found to be resistant to BA.5 replication. Conclusion(s): These results suggest that the BA.5 variant (lineage) of Omicron has the potential to regain the pathogenicity as it shows increased virulence compared to other Omicron sub-variants. Lethal infection of BA.5 in K18-hACE2 mice may be attributed to catastrophic encephalitis and increased cell-to-cell spread.
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Background and objectives: SARS-C0V-2 infections have varied manifestations among individuals ranging from asymptomatic or mild symptoms to severe disease and death. This study is done to look into various histopathological changes in lung, liver, and kidney tissues among Covid19 positive autopsies with cellular tropism and viral load among various organs by immunohistochemistry (IHC) for the SARS-C0V-2 viral marker. Method(s): A prospective descriptive study of core biopsies from covid19 positive autopsies from the lung, liver, and kidneys were taken from 20 cases. A routine histopathological examination of the tissues with IHC staining for SARS-CoV-2 cocktail antibodies was performed and assessed. Result(s): Histopathological changes in the lung, liver, and kidney tissues showed changes of varying severity. On IHC, in the lung, the tropism for SARS-CoV-2 was seen in pneumocytes, bronchial epithelial cells, endothelial cells, and macrophages. In the kidney, tropism was seen towards tubular epithelial cells and endothelial cells. In the liver, hepatocytes and bile duct epithelial cells were positive. Variable viral density was seen in different organs which varied from case to case. The density of the viral load was highest in the lung and lower in the kidney and least in the liver. Conclusion(s): In this study the various histopathological changes and cellular tropism of the SARS-CoV-2 among Lung, liver, and kidney tissues have been described and compared with various similar studies across the globe.Copyright © 2023 International Journal of Life Sciences Biotechnology and Pharma Research. All rights reserved.
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Purpose of Study: COVID pneumonia caused by SARS-CoV-2 can result in a depletion of surfactant & lung injury, which resembles neonatal respiratory distress syndrome. Exogenous surfactant has shown promise as a therapeutic option in intubated hospitalized patients. Our preliminary data in human lung organoids (LOs) with a deficiency of surfactant protein B (SP-B) showed an increased viral load compared to normal LOs. Single cell RNA sequencing (scRNAseq) revealed that SP-B-deficient cells showed increased viral entry genes (ACE2 receptor) & dysregulated inflammatory markers emanating from the lung cells themselves. Our objective was to determine: (1) cell-specific transcriptional differences between normal & SP-B deficient human lung cells after infection with SARS-CoV-2 and (2) a therapeutic role of SP-B protein & surfactant in COVID-19 pneumonia. Methods Used: We used normal and SP-B mutant (homozygous, frameshift, loss of function mutation p.Pro133GlnfsTer95, previously known as 121ins2) human induced pluripotent stem cells (hiPSC) and differentiated them into 3D proximal lung organoids. The organoids were infected with the delta variant of SARS-CoV-2 for 24 hours at an MOI of 1. Infected and uninfected organoids were fixed in trizol in triplicate and underwent processing for bulk RNA sequencing. We tested for differentially expressed genes using the program DEseq. We also plated normal iPSC derived lung organoids as a monolayer and pre-treated them with 1mg/ml of Poractant alfa or 5 uM of recombinant SP-B protein. The delta strain of SARS-CoV-2 was added to the 96 wells at an MOI of 0.1 for one hour with shaking, then an overlay with DMEM/CMC/FBS was added and left on for 23 hours. The plate was fixed and stained for nucleocapsid (NC) protein. Summary of Results: Bioinformatic analysis of the bulk RNA sequencing data showed an increase in the multiple cytokines and chemokines in the SP-B mutant LOs compared to control. We also saw differential gene expression patterns in the SP-B mutant LOs including a reduction in SFTPC, FOXA2, and NKX2-1 and an increase in IL1A, VEGFA, PPARG and SMAD3. In the exogenous surfactant experiments, there was a decrease in total expression of viral NC in the Poractant alfa & rSP-B-treated cells compared to SARS-CoV-2 infection alone (p<0.001). Conclusion(s): Surfactant modulates the viral load of SARS-CoV-2 infection in the human lung. Deficiency in SP-B results in the dysregulation of the lung epithelial inflammatory signaling pathways resulting in worsening infections.
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Background: Better understanding of host inflammatory changes that precede development of severe COVID-19 could improve delivery of available antiviral and immunomodulatory therapies, and provide insights for the development of new therapies. Method(s): In plasma from individuals with COVID-19, sampled <=10 days from symptom onset from the All-Ireland Infectious Diseases Cohort study, we measured 61 biomarkers, including markers of innate immune and T cell activation, coagulation, tissue repair, lung injury, and immune regulation. We used principal component analysis (PCA) and k-means clustering to derive biomarker clusters, and univariate and multivariate ordinal logistic regression to explore association between cluster membership and maximal disease severity, adjusting for risk factors for severe COVID-19, including age, sex, ethnicity, BMI, hypertension and diabetes. Result(s): From March 2020-April 2021, we included 312 individuals, (median (IQR) age 62 (48-77) years, 7 (4-9) days from symptom onset, 54% male) in the analysis. PCA and clustering derived 4 clusters. Compared to cluster 1, clusters 2-4 were significantly older and of higher BMI but there were no significant differences in sex or ethnicity. Cluster 1 had low levels of inflammation, cluster 2 had higher levels of markers of tissue repair and endothelial activation (EGF, VEGF, PDGF, TGFalpha, serpin E1 and p-selectin). Cluster 3 and 4 were both characterised by higher overall inflammation, but compared to cluster 4, cluster 3 had downregulation of growth factors, markers of endothelial activation, and immune regulation (IL10, PDL1), but higher alveolar epithelial injury markers (RAGE, ST2). In univariate analysis, compared to cluster 1, cluster 3 had the highest odds of severe disease (OR (95% CI) 9.02 (4.62-18.31), followed by cluster 4: 5.59 (2.75-11.72) then cluster 2: 4.5 (2.38-8.81), all p < 0.05). Cluster 3 remained most strongly associated with severe disease in fully adjusted analyses;cluster 3: OR(95% CI) 5.99 (2.69-13.35), cluster 2: 3.14 (1.54-6.42), cluster 4: 3.13 (1.36-7.19), all p< 0.05). Conclusion(s): Distinct early inflammatory profiles predicted maximal disease severity independent of known risk factors for severe COVID-19. A cluster characterised by downregulation of growth factor and endothelial markers and early evidence of alveolar injury was associated with highest risk of developing severe COVID19. Whether this reflects a dysregulated inflammatory response that could improve targeted treatment requires further study. Heatmap of biomarker derived clusters and forest plot of association between clusters and disease severity. A: Heatmap demonstrating differences in biomarkers between clusters B: Forest plot demonstrating odds ratio of specific clusters for progressing to moderate or severe disease (reference Cluster 1), calculated using ordinal logistic regression. Odds ratio (95% CI) presented as unadjusted and fully adjusted (for age, sex, ethnicity, BMI, hypertension, diabetes, immunosuppression, smoking and baseline anticoagulant use). Maximal disease severity graded per the WHO severity scale.
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Purpose of Study: The spread of SARS-CoV-2 and the resulting Coronavirus Disease 2019 (COVID-19) continues to manifest in individuals in varying severity with limited treatment options available. Despite research efforts put forth in developing therapeutic options for treatment of COVID-19 disease, effective and well understood mechanisms remain limited. Corticosteroid treatment with dexamethasone was shown to be beneficial for those with severe illness early in the pandemic with little understanding of its beneficial mechanism. This narrative review describes the current findings regarding the mechanism of action of dexamethasone treatment in the setting of SARS-CoV-2 infection. Methods Used: A comprehensive search of Embase and PubMed was conducted in consultation with a health sciences librarian. Search terms included (1) COVID-19 (2) dexamethasone (3) animal model and (4) immune response. No limits were used on the search and other reviews were excluded. Search results were screened based on titles and s before being selected for full text review. Outcomes recorded included characterization of the microenvironment of lung tissue following SARS-CoV-2 through cytokine measurement, histopathological staining and analysis of lung tissue, and clinical outcomes such as survival time. Summary of Results: The search resulted in 100 articles. Of these, 8 articles were identified that met the inclusion criteria. Three conducted experiments with Syrian hamsters, two with mice, two with alveolar macrophages, and one study was conducted with human subjects. Dexamethasone treatment was found to diminish inflammatory cytokine levels and preserve the integrity of lung tissue in several animal models and in vitro experiments in the setting of SARS-CoV-2 infection. Dexamethasone treatment was also found to reduce inflammatory cell infiltration of lung tissue infected with SARS-CoV-2. In humans, combination therapy of low dose dexamethasone with spironolactone proved more effective at lowering inflammatory markers than high dose dexamethasone alone. Conclusion(s): Collectively, the articles included in this review support the use of dexamethasone treatment in SARS-CoV-2 infection. Protective effects exhibited with dexamethasone treatment suggest that its action may be linked to the inflammatory nature of COVID-19 disease. Macrophage regulation and diminished inflammatory cytokine levels were hypothesized as possible mechanistic features of dexamethasone action but lacked exact characterization. Further exploration of combination treatment with dexamethasone and its mechanism of action is needed to identify specific and effective therapeutic strategies in the future.
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Introduction/Aim: We previously reported impaired pulmonary gas exchange in acute COVID-19 patients resulting from both increased intrapulmonary shunt (SH) and increased alveolar dead space (AD) 1 . The present study quantifies gas exchange in recovered patients. Method(s): Unvaccinated patients diagnosed with acute COVID-19 infection (March-December 2020) were studied 15 to 403 days post first SARS-CoV-2 positive PCR test. Demographic, anthropometric, acute disease severity and comorbidity data were collected. Breathing room air, steady-state exhaled gas concentrations were measured simultaneously with arterial blood gases. Alveolar CO 2 and O 2 (P A CO 2 and P A O 2 ;mid-exhaled volume) determined;AaPO2, aAPCO2, SH% and AD% calculated. 2 Results: We studied 59 patients (33 males, Age: 52[38-61] years, BMI: 28.8[25.3-33.6] kg/m 2 ;median[IQR]). Co-morbibities included asthma (n = 2), cardiovascular disease (n = 3), hypertension (n = 12), and diabetes (n = 9);14 subjects smoked;44 had experienced mild-moderate COVID-19 (NIH category 1-2), 15 severe-critical disease (NIH category 3-5). PaCO 2 was 39.4[35.6-41.1] mmHg, PaO 2 92.1[87.1-98.2] mmHg;P A CO 2 32.8[28.6-35.3] mmHg, P A O 2 112.9[109.4-117.0] mmHg, AaPO 2 18.8[12.6-26.8] mmHg, aAPCO 2 5.9[4.3-8.0] mmHg, SH 4.3 [2.1-5.9]% and AD 16.6 [12.6-24.4]%. 14% of patients had normal SH (<5%) and AD (<10%);1% abnormal SH and normal AD;36% both abnormal SH and AD;49% normal shunt and abnormal AD. Previous severe-critical disease was a strong independent predictor for increased SH (OR 14.8[2.28-96], [95% CI], p < 0.01), increasing age weakly predicted increased AD (OR 1.18[1.01, 1.37], p < 0.04). Time since infection, BMI and comorbidities were not significant predictors (all p > 0.11). Conclusion(s): Prior COVID-19 was associated with increased intrapulmonary shunt and/or increased alveolar dead space in 86% of this cohort up to ~13 months post infection, with those with more severe acute disease, and older patients, at greater risk. Increased intrapulmonary shunt suggests persistent alveolar damage, while increased alveolar dead space may indicate persistent pulmonary vascular occlusion.
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Background: Plasmacytoid dendritic cells (pDCs) are the major producer of type I IFNs (IFN-I), the critically important antiviral cytokines against SARS-CoV- 2. Although pDCs can sense cell-free SARS-CoV-2 virions, it is unknown whether they can detect infected cells to produce IFN-I. Since cell-to-cell transmission accounts for 90% of SARS-CoV-2 infections (Zeng et al., 2022), we examined the relevance of pDC sensing of infected cells in SARS-CoV-2 infection and whether the virus exploits this pathway to evade IFN-I responses. Method(s): LSPQ1, the first SARS-CoV-2 clinical isolate received from the Public Health Laboratory of Quebec, was used as a prototype virus. SARS-CoV-2 variants of concerns (VOCs) were also used. PBMCs or enriched pDCs were cocultured with mock-infected or SARS-CoV-2-infected HeLa-hACE2 or Calu-3. Either PBMCs, enriched pDCs, or HeLa-hACE2 were pretreated with anti-human ICAM-1 antibody or isotype control. The conjugate formation was determined by flow cytometry. Polarized Caco cells were used to validate critical data. Result(s): Upon sensing infected cells, PBMCs release 6-fold more IFN-I than they do when exposed to cell-free virions. Antibody-mediated depletion of pDCs from PBMCs abolishes IFN-I secretion. Direct contact of pDCs with infected cells is required for sensing since the use of a transwell membrane reduces IFN-I release by 85%. Infected cells form conjugates with pDCs more frequently (3.2-fold higher) than uninfected cells. Blocking ICAM-1 on infected cells or pDCs impacts conjugate formation and significantly suppresses IFN-I production by 55-80%, suggesting bidirectional interaction. Moreover, human lung cells infected with VOCs are sensed to a different extent with the alpha variant being the least efficiently sensed by pDCs compared to the delta or omicron strains. Even though SARS-CoV-2 is primarily released from the apical domain of polarized infected Caco cells, sensing of infected cells does occur upon direct contact of pDCs with the basolateral domain, highlighting how pDCs antiviral responses might be triggered in respiratory tissues. Conclusion(s): pDC sensing of infected cells accounts for the vast majority of IFN-I released during SARS-CoV-2 infection. ICAM-1 promotes physical contact between pDCs and infected cells, thus leading to efficient sensing. Differential pDC sensing of SARS-CoV-2 VOC-infected cells suggests that some VOCs might manipulate the interactions of pDCs with infected cells to limit IFN-I responses.
ABSTRACT
Background: Natural killer (NK) cells play a critical role in control of viral infections. However, empirical evidence thus far has been unclear on the role of NK cells in pathogenesis and control of SARS-CoV-2 infection with some research suggesting NK cell accumulation as beneficial while others indicate it as deleterious. To address this crucial deficit in understanding, we employed a non-human primate infection model with a validated experimental NK cell depletion technique. Method(s): A total of 12 experimentally naive (75% female) cynomolgus macaques (CM) of Cambodian origin were used in this study. Six CM were NK cell-depleted using an anti-IL-15 neutralizing antibody, while six controls received placebo, prior to intranasal and intratracheal challenge with the SARS-CoV-2 Delta variant at a TCID50 of 1X105. The cohort was monitored for five weeks with scheduled blood, colorectal (CR) biopsies, and lymph node (LN) collections. Total envelope and sub-genomic viral loads (VL) were measured in the nasal cavity, throat, and bronchoalveolar lavage (BAL). 23-color flow cytometry, pathology, and 27-plex inflammatory analyte Luminex analyses were conducted. Statistical tests used were Mann-Whitney U and Spearman's Correlation. Result(s): Control CM exhibited an increase in the frequency of circulating NK cells, reaching a peak at 10 days post-infection (DPI) and returning to baseline by 22DPI. Simultaneously, NK cells expressing activation and tissue retention marker, CD69, also significantly increased. Cytotoxic NK cells were positively associated with VL (r=0.66;p=0.02), suggestive of a virus-induced mobilization. Total experimental NK cell ablation was verified in blood, CR, and LN of NK celldepleted CM, which had higher VL compared to controls in all tissues evaluated, reaching significance at 10DPI (p=0.01) and demonstrated a longer duration of viremia. Although Luminex measures were similar in plasma, BAL samples from NK cell-depleted CM had universally higher concentrations of inflammatory mediators, most notably a 25-fold higher concentration of IFN-alpha compared to controls. Lung pathology scores were also higher in NK cell-depleted CM with increased evidence of fibrosis, syncytia, pneumocyte hyperplasia, and endothelialitis. Conclusion(s): Overall, we find significant and conclusive evidence for NK cell-mediated control of SARS-CoV-2 virus replication and disease pathology. These data suggest adjunct therapies for infection could largely benefit from NK cell-targeted approaches.
ABSTRACT
Since December 2019, an outbreak of a novel coronavirus (SARS-CoV-2) infection causing COVID-19 disease has influenced the whole world. Angiotensin converting enzyme 2 (ACE2) receptors on type 2 pneumocytes in humans were determined as the entry for SARSCoV-2. Receptor binding and subsequently endocytosis of ACE2 diminish the cell membrane expression and also the function of ACE2. ACE2 is an enzyme involved in bradykinin metabolism. Lys-des-Arg9-BK occured with enzymatic cleaving of Lys-BK derived from low molecular weight kininogen is inactivated by ACE2 in tissues and it is a vasodilator agent having its own receptor named bradykinin B1. Non-metabolized Lys-des-Arg9-BK can be the reason for tissue vasodilation and increased vascular permeability in the patients with COVID-19. Increased bradykinin levels in patients with hereditary angioedema with C1-INH deficiency (C1-INH-HAE) do not cause increased SARS-CoV-2 infection or more severe disease. Although SARS-CoV-2 infection does not result in increased bradykinin levels, it can increase Lys-des-Arg9-BK levels.Copyright © 2020 Bilimsel Tip Yayinevi. All rights reserved.
ABSTRACT
Introduction/Aim: Coronavirus disease 2019 (COVID-19) is a novel viral infection that can cause severe pneumonia and acute respiratory failure;however, the mechanism of disease progression is still unclear. The aim of this study is to evaluate inflammatory cells in the lung by analysing cell populations of bronchial aspirates of COVID-19 pneumonia. Method(s): Eligible cases were diagnosed as COVID-19, confirmed by SARS-CoV-2 PCR. All cases had developed severe COVID-19 pneumonia and undergone invasive positive pressure ventilation for the treatment of respiratory failure. Bronchial aspirates were collected during endotracheal intubation, and SARS-CoV-2 PCR was done. The populations of obtained cells from bronchial aspirates were examined by Giemsa staining and immunohistochemical staining of CD3, CD4, CD8, CD20 and CD68 antigens. Bronchial aspirates were cultured to confirm respiratory bacterial co-infections. Result(s): A total of 14 cases (median age 70;eleven male and three female) were enrolled in this study. Their bronchial aspirates were all positive for SARS-CoV-2 PCR. Bacterial co-infections were developed in 10 cases, including 6 cases of pneumonia/respiratory tract infection, 2 cases of sepsis, and 2 cases of urinary tract infection. Cell populations of bronchial aspirates with or without bacterial co-infections were as follows: neutrophils 33.0% vs. 21.5%;CD3+ mononuclear cells (MNCs) 2.5% vs. 5.8%;CD4+ MNCs 4.6% vs. 3.4%;CD8+ MNCs 3.5% vs. 5.2%;CD20+ MNCs 0.2% vs. 0.1%;CD68+ MNCs 39.7% vs. 38.8%, respectively. Conclusion(s): CD68 antigen is mainly expressed in monocytes/macrophages. CD68+ MNCs were dominant in bronchial aspirates of the cases with severe COVID-19 pneumonia. Our data suggests that CD68+ MNCs, presumably macrophages, would play an essential role during the innate immune response to acute SARS-CoV-2 infection in the lung.