Differential effects of age, sex and dexamethasone therapy on ACE2/TMPRSS2 expression and susceptibility to SARS-CoV-2 infection.

ACE2 and TMPRSS2 are crucial for SARS-CoV-2 entry into the cell. Although ACE2 facilitates viral entry, its loss leads to promoting the devastating clinical symptoms of COVID-19 disease. Thus, enhanced ACE2/TMPRSS2 expression is likely to increase predisposition of target cells to SARS-CoV-2 infection. However, little evidence existed about the biological kinetics of these two enzymes and whether dexamethasone treatment modulates their expression. Here, we show that the expression of ACE2 at the protein and mRNA levels was significantly higher in the lung and heart tissues of neonatal compared to adult mice. However, the expression of TMPRSS2 was developmentally regulated. Our results may introduce a novel concept for the reduced susceptibility of the young to SARS-CoV-2 infection. Moreover, ACE2 expression but not TMPRSS2 was upregulated in adult female lungs compared to their male counterparts. Interestingly, the ACE2 and TMPRSS2 expressions were upregulated by dexamethasone treatment in the lung and heart tissues in both neonatal and adult mice. Furthermore, our findings provide a novel mechanism for the observed differential therapeutic effects of dexamethasone in COVID-19 patients. As such, dexamethasone exhibits different therapeutic effects depending on the disease stage. This was supported by increased ACE2/TMPRSS2 expression and subsequently enhanced infection of normal human bronchial epithelial cells (NHBE) and Vero E6 cells with SARS-CoV-2 once pre-treated with dexamethasone. Therefore, our results suggest that individuals who take dexamethasone for other clinical conditions may become more prone to SARS-CoV-2 infection.

COVID -19 Pandemic Diseases Effect on Self-Medication Practices Among Community of Bedelle City and Its Surrounding, Buno Bedelle Zone, South West of Oromia, Ethiopia (preprint)

Abstract Introduction There is a clear link between self-medication practice and ongoing pandemic diseases like COVID-19, According to studies conducted globally and the general Ethiopian population turned to self-medication and symptomatic treatment as a result of inadequate COVID-19 treatment and also about 80% of the population amassed drugs for pandemic use. Objective: The objective of this study was to assess self-medication practice for treatment of Covid-19 and reason to use self- medication among residents in Bedelle city and its surrounding, Southwest Oromia, Ethiopia. Methodology: A cross sectional study design was employed and the standardized questionnaire was developed by reviewing relevant literatures then the data was collected using face to face interview. Final data was analyzed by using SPSS version 23. Result: The final study contained 415 respondents in total, with a response rate of 98.5%. The majority of responses were females and between the ages of 18 - 25 Category. In this study population, the use of self-medication since the onset of the Covid-19 epidemic was reported by participants were around 50.6%. Analgesics (42.4%) and cold medicines (29.5%) were the most frequently used medications for treatment of COVID-19. Also the reported uses of these drugs included treatment of Covid-19 symptoms like the Headache (22.2%), Fever (13.2%), respiratory infective (14.3%), and cold (21.4%) were the most frequently reported symptoms for self-medication. Self-medication methods were used more frequently by women than Men. Conclusion: According to this study, analgesics and cold medications are commonly self- medicated drugs used for Covid-19 therapy. It is a serious health concern, particularly when COVID-19 symptoms are present, and high consumption of self-medication has been linked to COVID-19 prevention or treatment. Key words: Covid-19, Medicine, Practice, Bedelle city, Self-Medication

Differential Impact of SARS-CoV-2 Isolates, Namely, the Wuhan Strain, Delta, and Omicron Variants on Erythropoiesis.

SARS-CoV-2 variants exhibit different viral transmissibility and disease severity. However, their impact on erythropoiesis has not been investigated. Here, we show SARS-CoV-2 variants differentially affect erythropoiesis. This is illustrated by the abundance of CD71+ erythroid cells (CECs) in the blood circulation of COVID-19 patients infected with the original Wuhan strain followed by the Delta and Omicron variants. We observed the CD45+CECs are the dominant subpopulation of CECs expressing the receptor, ACE2, and coreceptor, TMPRSS2, and thus, can be targeted by SARS-CoV-2. Also, we found CECs exhibit immunosuppressive properties, specifically CD45+CECs are the dominant immunosuppressive cells and via reactive oxygen species (ROS) and arginase I expression can impair CD8+ T cell functions. In agreement, we observed CECs suppress CD8+ T cell effector (e.g., Granzyme B expression and degranulation capacity [CD107]), which was partially but significantly reversed with l-arginine supplementation. In light of the enriched frequency of CECs, in particular, CD45+CECs in patients infected with the original (Wuhan) strain, we believe this strain has a more prominent impact on hematopoiesis compared with the Delta and Omicron variants. Therefore, our study provides an important insight into the differential impact of SARS-CoV-2 variants on erythropoiesis in COVID-19 patients. IMPORTANCE Silent hypoxia has been the hallmark of SARS-CoV-2 infection. Red blood cells (RBCs) work as gas cargo delivering oxygen to different tissues. However, their immature counterparts reside in the bone marrow and normally absent in the blood circulation. We show SARS-CoV-2 infection is associated with the emergence of immature RBCs so called CD71+ erythroid cells (CECs) in the blood. In particular, we found these cells were more prevalent in the blood of those infected with the SARS-CoV-2 original strain (Wuhan) followed by the Delta and Omicron variants. This suggests SARS-CoV-2 directly or indirectly impacts RBC production. In agreement, we observed immature RBCs express the receptor (ACE2) and coreceptor (TMPRSS2) for SARS-CoV-2. CECs suppress T cells functions (e.g., Granzyme B and degranulation capacity) in vitro. Therefore, our study provides a novel insight into the differential impact of SARS-CoV-2 variants on erythropoiesis and subsequently the hypoxia commonly observed in COVID-19 patients.

The Quality of SARS-CoV-2-Specific T Cell Functions Differs in Patients with Mild/Moderate versus Severe Disease, and T Cells Expressing Coinhibitory Receptors Are Highly Activated.

Understanding the function of SARS-CoV-2 Ag-specific T cells is crucial for the monitoring of antiviral immunity and vaccine design. Currently, both impaired and robust T cell immunity is described in COVID-19 patients. In this study, we explored and compared the effector functions of SARS-CoV-2-reactive T cells expressing coinhibitory receptors and examine the immunogenicity of SARS-CoV-2 S, M, and N peptide pools in regard to specific effector T cell responses, Th1/Th2/Th17, in COVID-19 patients. Analyzing a cohort of 108 COVID-19 patients with mild, moderate, and severe disease, we observed that coinhibitory receptors (e.g., PD-1, CTLA-4, TIM-3, VISTA, CD39, CD160, 2B4, TIGIT, Gal-9, and NKG2A) were upregulated on both CD4+ and CD8+ T cells. Importantly, the expression of coinhibitory receptors on T cells recognizing SARS-CoV-2 peptide pools (M/N/S) was associated with increased frequencies of cytokine-producing T cells. Thus, our data refute the concept of pathological T cell exhaustion in COVID-19 patients. Despite interindividual variations in the T cell response to viral peptide pools, a Th2 phenotype was associated with asymptomatic and milder disease, whereas a robust Th17 was associated with severe disease, which may potentiate the hyperinflammatory response in patients admitted to the Intensive Care Unit. Our data demonstrate that T cells may either play a protective or detrimental role in COVID-19 patients. This finding could have important implications for immune correlates of protection, diagnostic, and prophylaxis with respect to COVID-19 management.

Crystal structure and mol-ecular docking study of (E)-2-{[(E)-2-hy-droxy-5-methyl-benzyl-idene]hydrazinyl-idene}-1,2-di-phenyl-ethan-1-one.

The title compound, C22H18N2O2, is a Schiff base that exists in the phenol-imine tautomeric form and adopts an E configuration with respect to the C=N bond. The mol-ecular structure is stabilized by an O-H⋯N hydrogen bond, forming an S(6) ring motif. In the crystal, pairs of C-H⋯O hydrogen bonds link the mol-ecules to form inversion dimers. Weak π-π stacking inter-actions along the a-axis direction provide additional stabilization of the crystal structure. The mol-ecule is non-planar, the aromatic ring of the benzaldehyde residue being nearly perpendicular to the phenyl and 4-methyl-phenol rings with dihedral angles of 88.78 (13) and 82.26 (14)°, respectively. A mol-ecular docking study between the title mol-ecule and the COVID-19 main protease (PDB ID: 6LU7) was performed, showing that it is a potential agent because of its affinity and ability to adhere to the active sites of the protein.

Erythroid precursors and progenitors suppress adaptive immunity and get invaded by SARS-CoV-2.

SARS-CoV-2 infection is associated with lower blood oxygen levels, even in patients without hypoxia requiring hospitalization. This discordance illustrates the need for a more unifying explanation as to whether SARS-CoV-2 directly or indirectly affects erythropoiesis. Here, we show significantly enriched CD71+ erythroid precursors/progenitors in the blood circulation of COVID-19 patients. We found that these cells have distinctive immunosuppressive properties. In agreement, we observed a strong negative correlation between the frequency of these cells with T and B cell proportions in COVID-19 patients. The expansion of these CD71+ erythroid precursors/progenitors was negatively correlated with the hemoglobin levels. A subpopulation of abundant erythroid cells, CD45+ CD71+ cells, co-express ACE2, TMPRSS2, CD147, and CD26, and these can be infected with SARS-CoV-2. In turn, pre-treatment of erythroid cells with dexamethasone significantly diminished ACE2/TMPRSS2 expression and subsequently reduced their infectivity with SARS-CoV-2. This provides a novel insight into the impact of SARS-CoV-2 on erythropoiesis and hypoxia seen in COVID-19 patients.

Galectin-9, a Player in Cytokine Release Syndrome and a Surrogate Diagnostic Biomarker in SARS-CoV-2 Infection.

The outbreak of SARS-CoV-2 infection has enormously impacted our lives. Clinical evidence has implicated the emergence of cytokine release syndrome as the prominent cause of mortality in COVID-19 patients. In this study, we observed massive elevation of plasma Galectin-9 (Gal-9) in COVID-19 patients compared to healthy controls (HCs). By using the receiver operating characteristic (ROC) curve, we found that a baseline of 2,042 pg/ml plasma Gal-9 can differentiate SARS-CoV-2-infected from noninfected individuals with high specificity/sensitivity (95%). Analysis of 30 cytokines and chemokines detected a positive correlation of the plasma Gal-9 with C-reactive protein (CRP) and proinflammatory cytokines/chemokines such as interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), IP-10, MIP-1α, and MCP-1 but an inverse correlation with transforming growth factor ß (TGF-ß) in COVID-19 patients. In agreement, we found enhanced production of IL-6 and TNF-α by monocytes and NK cells of COVID-19 patients once treated with the recombinant human Gal-9 in vitro Also, we observed that although the cell-membrane expression of Gal-9 on monocytes does not change in COVID-19 patients, those with higher Gal-9 expression exhibit an activated phenotype. Furthermore, we noted significant downregulation of surface Gal-9 in neutrophils from COVID-19 patients compared to HCs. Our further investigations indicated that immune activation following SARS-CoV-2 infection results in Gal-9 shedding from neutrophils. The strong correlation of Gal-9 with proinflammatory mediators suggests that inhibition of Gal-9 may severe as a therapeutic approach in COVID-19 infection. Besides, the plasma Gal-9 measurement may be used as a surrogate diagnostic biomarker in COVID-19 patients.IMPORTANCE The outbreak of SARS-CoV-2 infection has enormously impacted our lives. Clinical evidence has implicated the emergence of cytokine release syndrome as the prominent cause of mortality in COVID-19 patients. We observed substantial elevation of the plasma Galectin-9 (Gal-9) in COVID-19 patients compared to healthy controls. Gal-9 is an abundant protein in many immune and nonimmune cells. We found that Gal-9 detection assay can differentiate SARS-CoV-2-infected from noninfected individuals with a specificity/sensitivity of 95%. Importantly, we found a positive correlation of the plasma Gal-9 with a wide range of proinflammatory biomarkers in COVID-19 patients. In agreement, we found enhanced expression and production of such proinflammatory molecules by immune cells of COVID-19 patients once treated with Gal-9 in vitro Our results propose Gal-9 as an important contributing factor in cytokine release syndrome; therefore, Gal-9 inhibition may serve as a beneficial therapeutic approach by suppressing the hyperimmune activation in COVID-19 patients.

Do COVID-19 Infections Result in a Different Form of Secondary Hemophagocytic Lymphohistiocytosis.

The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has resulted in significant morbidity and mortality across the world, with no current effective treatments available. Recent studies suggest the possibility of a cytokine storm associated with severe COVID-19, similar to the biochemical profile seen in hemophagocytic lymphohistiocytosis (HLH), raising the question of possible benefits that could be derived from targeted immunosuppression in severe COVID-19 patients. We reviewed the literature regarding the diagnosis and features of HLH, particularly secondary HLH, and aimed to identify gaps in the literature to truly clarify the existence of a COVID-19 associated HLH. Diagnostic criteria such as HScore or HLH-2004 may have suboptimal performance in identifying COVID-19 HLH-like presentations, and criteria such as soluble CD163, NK cell activity, or other novel biomarkers may be more useful in identifying this entity.

Venous Thromboembolism Has a Variable Time of Occurrence in the Course of COVID-19: A Case Series.

The novel severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) which results in coronavirus disease 2019 (COVID-19) has had a devastating impact globally. Not much is fully understood about this disease. Acute respiratory distress syndrome (ARDS) appears to be the commonest complication among patients with COVID-19. However, venous thromboembolism (VTE) appears to be a common complication among patients with COVID-19 even with adequate anticoagulation during hospitalization. VTE may confer a poor outcome on its own or may exacerbate other common complications such as ARDS or cardiac injury. There are several diagnostic dilemmas with regards confirming VTE among patients with COVID-19 as there is a move to reduce the transfer of patients for angiographic studies or even venous Doppler ultrasonography because of the high transmissibility SARS-CoV-2. There is also the risk of worsening ARDS following fluid administration to prevent contrast nephropathy after angiographic studies.  It is, therefore, crucial to understand the timing of VTE occurrence in the setting of COVID-19, identify strategies for early diagnosis of VTE, therapeutic options as well as prognostic implications of VTE in the setting of COVID-19.

COVID-19, rheumatic diseases and immune dysregulation-a perspective.

The COVID-19 pandemic has resulted in widespread hospitalisations and deaths around the world. As patients with rheumatic diseases generally have increased risk of infections and complications, understandably, there is significant concern of the impact of SARS-CoV-2 on these patients. However, there is a paucity of data in rheumatic patients. We review mechanisms through which SARS-CoV-2 results in infection, including ACE2 receptor, and complications (including immune dysregulation, thrombosis and complement activation). We assess these pathways in patients with rheumatic disease and those on immune modulating therapy. Although data thus far does not appear to show worse outcomes in rheumatic patients as a whole, given alterations in the underlying immune pathways in certain diseases (such as systemic lupus erythematosus), we posit that the risk is not equal in all rheumatic patients. We also discuss the benefit of underlying disease control with respect to COVID-19 risk reduction and potential increased risk of disease flares following viral infection from an immune standpoint.

Insertion technique for the Impella 5.0 heart pump in the COVID-19 era.

We describe the insertion of the Impella 5.0, a peripherally placed mechanical cardiovascular microaxial pump, in a patient with ischemic left ventricular dysfunction. The Impella is a 7 Fr device capable of achieving a flow of 4.0-5.0 L/min; its use necessitates an open arterial cut-down. A subclavicular incision is used to access the right or left axillary artery. A 10-mm tube graft is anastomosed to the artery through which the Impella 5.0 is inserted. The device traverses the tube graft and is advanced via the aorta, across the aortic valve, to its final position (inflow toward the ventricular apex and outflow above the aorta). The device may remain in situ for 10 days until recovery or until further supports are instituted. Our goal is to demonstrate the insertion of the Impella 5.0 device in a patient with cardiogenic shock whose situation was further complicated by coronavirus disease 2019.

Impaired natural killer cell counts and cytolytic activity in patients with severe COVID-19.

The global pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-driven coronavirus disease 2019 (COVID-19) has caused unprecedented human death and has seriously threatened the global economy. Early data suggest a surge in proinflammatory cytokines in patients with severe COVID-19, which has been associated with poor outcomes. We recently postulated that the inflammatory response in patients with severe COVID-19 disease is not inhibited by natural killer (NK) cells, resulting in a "cytokine storm." Here, we assessed the NK-cell functional activity and the associated cytokines and soluble mediators in hospitalized COVID-19 patients. Significantly impaired NK-cell counts and cytolytic activity were observed in COVID-19 patients when compared with healthy controls. Also, cytokines like interleukin 12 (IL12), IL15, and IL21 that are important for NK-cell activity were not detected systematically. Serum concentrations of soluble CD25 (sCD25)/soluble IL2 receptor α (sIL2-Rα) were significantly elevated and were inversely correlated with the percentage of NK cells. Impaired NK-cell cytolytic activity together with other laboratory trends including elevated sCD25 were consistent with a hyperinflammatory state in keeping with macrophage-activation syndrome. Our findings suggest that impaired counts and cytolytic activity of NK cells are important characteristics of severe COVID-19 and can potentially facilitate strategies for immunomodulatory therapies.

Elevated D-Dimer Levels Are Associated With Increased Risk of Mortality in Coronavirus Disease 2019: A Systematic Review and Meta-Analysis.

The 2019 novel coronavirus, declared a pandemic, has infected 2.6 million people as of April 27, 2020, and has resulted in the death of 181,938 people. D-dimer is an important prognostic tool, is often elevated in patients with severe coronavirus disease-19 (COVID-19) infection and in those who suffered death. In this systematic review, we aimed to investigate the prognostic role of D-dimer in COVID-19-infected patients. We searched PubMed, Medline, Embase, Ovid, and Cochrane for studies reporting admission D-dimer levels in COVID-19 patients and its effect on mortality. Eighteen studies (16 retrospective and 2 prospective) with a total of 3682 patients met the inclusion criteria. The pooled weighted mean difference (WMD) demonstrated significantly elevated D-dimer levels in patients who died versus those who survived (WMD, 6.13 mg/L; 95% confidence interval [CI] 4.16-8.11; P < 0.001). Similarly, the pooled mean D-dimer levels were significantly elevated in patients with severe COVID-19 infection (WMD, 0.54 mg/L; 95% CI 0.28-0.80; P < 0.001). The risk of mortality was fourfold higher in patients with positive D-dimer versus negative D-dimer (risk ratio, 4.11; 95% CI, 2.48-6.84; P < 0.001) and the risk of developing severe disease was twofold higher in patients with positive D-dimer levels versus negative D-dimer (risk ratio, 2.04; 95% CI, 1.34-3.11; P < 0.001). Our meta-analysis demonstrates that patients with COVID-19 infection presenting with elevated D-dimer levels have an increased risk of severe disease and mortality.

Natural Killer Cell Dysfunction and Its Role in COVID-19.

When facing an acute viral infection, our immune systems need to function with finite precision to enable the elimination of the pathogen, whilst protecting our bodies from immune-related damage. In many instances however this "perfect balance" is not achieved, factors such as ageing, cancer, autoimmunity and cardiovascular disease all skew the immune response which is then further distorted by viral infection. In SARS-CoV-2, although the vast majority of COVID-19 cases are mild, as of 24 August 2020, over 800,000 people have died, many from the severe inflammatory cytokine release resulting in extreme clinical manifestations such as acute respiratory distress syndrome (ARDS) and hemophagocytic lymphohistiocytosis (HLH). Severe complications are more common in elderly patients and patients with cardiovascular diseases. Natural killer (NK) cells play a critical role in modulating the immune response and in both of these patient groups, NK cell effector functions are blunted. Preliminary studies in COVID-19 patients with severe disease suggests a reduction in NK cell number and function, resulting in decreased clearance of infected and activated cells, and unchecked elevation of tissue-damaging inflammation markers. SARS-CoV-2 infection skews the immune response towards an overwhelmingly inflammatory phenotype. Restoration of NK cell effector functions has the potential to correct the delicate immune balance required to effectively overcome SARS-CoV-2 infection.

A case report of unusually long episodes of asystole in a severe COVID-19 patient treated with a leadless pacemaker.

BACKGROUND: Experience has been emerging about cardiac manifestations of COVID-19-positive patients. The full cardiac spectrum is still unknown, and management of these patients is challenging. CASE SUMMARY: We report a COVID-19 patient who developed unusually long asystolic pauses associated with atriventricular block (AV) block and atrial fibrillation who underwent leadless pacemaker implantation. DISCUSSION: Asystole may be a manifestation of COVID-19 infection. A leadless pacemaker is a secure remedy, with limited requirements for follow-up, close interactions, and number of procedures in a COVID-19 patient.

Epitope‐based peptide vaccine design against spike protein (S) of novel coronavirus (2019-nCoV): an immunoinformatics approach (preprint)

Background Recently the global pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has generated a significant need on identifying drugs or vaccines to prevent or reduce clinical infection of Coronavirus disease – 2019 (COVID-19). In this study, immuno-informatics tools were utilized to design a potential multi-epitopes vaccine against SARS-CoV-2 spike S protein. Structural analysis for SARS-CoV-2 spike S protein was also conducted.Method: SARS-CoV-2 spike S protein sequences were retrieved from the GeneBank of National Central Biotechnology Information (NCBI). Immune Epitope Database (IEDB) tools were used to predict B and T cell epitopes, to evaluate their allergenicity, toxicity and cross- reactivity and to calculate population coverage. Protparm sever was applied to determine protein characterization of spike protein and predicted epitopes. Molecular docking for the proposed MHCI epitopes were also achieved against Tall like Receptor (TLR8) receptors and HLA-B7 allele.Result Immuno-informatics analysis of S protein using IEDB identified only one B cell epitope 1054QSAPH1058 as linear, surface and antigenic. Although 1054QSAPH1058 was estimated as non-allergic and non-toxic, it showed protein instability. Moreover, around 45 discontinuous epitopes were also recognized as different exposed surface area. In MHCI methods, six conserved stable and safe epitopes (898FAMQMAYRF906, 258WTAGAAAYY266 and 2FVFLVLLPL10, 202 KIYSKHTPI210, 712IAIPTNFTI720 and 1060VVFLHVTYV1068) were identified. These epitopes showed strong interaction when docked with TLR8 and HLA-B7 allele especially 1060VVFLHVTYV1068 and 2FVFLVLLPL10 epitopes. Three epitopes were also predicted (898FAMQMAYRF906, 888FGAGAALQI896 and 342FNATRFASV350) using MHCII methods. Furthermore, the potential multi-epitopes were acquired by assessing allergenicity, toxicity and cross-reactivity to prevent autoimmunity.Conclusion The multi-epitopes vaccine was predicted based on Bioinformatics tools that may provide reliable results in a shorter time and at a lower cost. However, further in vivo and in vitro studies are required to validate their effectiveness.