ABSTRACT
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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Introduction: De novo donor specific antibodies (DSAs) are associated with increased risk of antibody-mediated rejection (AMR) and worse prognosis in patients after orthotopic heart transplant (OHT). Viral infections have the potential to induce or reactivate the production of DSAs, yet the development of DSAs after infection by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has not been reported. In this observational study, we describe DSA titers after Coronavirus Disease 2019 (COVID-19) infection and relationship with AMR and graft dysfunction in a large OHT cohort at a tertiary academic medical center. Hypothesis: : We predicted that COVID-19 infection would be associated with development of de novo DSAs or increase in pre-existing DSAs. Method(s): We retrospectively analyzed all adult OHT patients followed at Washington University School of Medicine in St. Louis between 4/1/2020-12/31/2021. COVID-19 infection was defined by positive antigen or PCR test in setting of clinical exposure or symptoms. Patients were considered fully vaccinated 2 weeks after 2 doses of the BNT162b (Pfizer-BioNTech) or mRNA-1273 (Moderna) vaccines or after a single dose of the AD26.COV2.S (Johnson & Johnson) vaccine. De novo DSAs were defined as newly detected MHC I or II antibody greater than 2000 mean fluorescence intensity (MFI) by single antigen beads or newly elevated antibody against angiotensin-II type 1 receptor (AT1R). In patients with pre-existing DSAs, a significant increase was defined by an MFI value that increased by 20% or more compared to their baseline value prior to SARS-CoV-2 infection. Result(s): A total of 577 patients were followed during the study period and 117 cases of COVID-19 infection were identified. Baseline characteristics of COVID-19 positive patients are shown in Figure. Overall, 10% of patients infected with SARS-CoV-2 infection developed de novo DSAs or an increase in pre-existing DSAs, with unvaccinated patients having a higher incidence compared to vaccinated patients (15% vs. 2%, p=0.02). MHC class II-specific antibodies were the most common DSAs detected. There was a trend towards higher incidence of AMR in unvaccinated patients, although mortality and long-term graft dysfunction were similar. Conclusion(s): Unvaccinated patients had a higher incidence of developing de novo or an increase in pre-existing DSAs after SARS-CoV-2 infection. Future studies are necessary to investigate the long-term consequences of COVID-19 in the OHT population.Copyright © 2022
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Background: Acute respiratory distress syndrome (ARDS) is a distinctive feature of severe COVID-19 infections that occurs mainly in patients with coexisting health problems, such as hypertension, atherosclerosis, and diabetes. Endothelial dysfunction is a major contributing factor during ARDS development in COVID- 19 patients with pre-existing comorbidities. Objective: Studying the mechanism by which endothelial activation and dysfunction could provide a therapeutic target for COVID-19 treatment. Design and method: The current study measured endothelial dysfunction and oxidative stress by incubating human umbilical vein endothelial cells (HUVECs) with plasma from patients with mild, moderate, severe and extremely severe COVID- 19. Using flow cytometry, wound-healing assays and phosphokinase arrays, Results: We detected increases in cell apoptosis;reactive oxygen species (ROS) formation;hypoxia-inducible factor-1 alpha (HIF-1 alpha), vascular cell adhesion molecule-1 (VCAM-1), and vascular endothelial growth factor receptor-1 (VEGFR-1) expression;viral entry;and inflammatory-related protein activity. We also found an impairment in the wound-healing process. Moreover, we found that AT1R blockade and P38 MAPK inhibition reversed all of these effects, especially in the severe group. Conclusions: These findings indicate that AT1R/P38 MAPK-mediated oxidative stress and endothelial dysfunction occur during COVID-19 infection.
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Infection by the Covid-19 produces in people an illness of profoundly factor and erratic seriousness. The presence of continuous hereditary single nucleotide polymorphisms (SNPs) in the population could prompt a more prominent weakness to infections or an overstated provocative reaction. We concentrated on the relationship between SNP from AGTR1 gene and the seriousness of the infection created by the SARS-Cov-2 infection. Methods: 30 (18 of male and 12 of Female) Covid-19 patients with age range from 55-60 years were assembled in light of the seriousness of side effects. Results: one SNP rs5186 in AGTR1 gene were related with the seriousness of illness. Our results were showed that the rs5186 (C) allele in AGTR1 gene is associated with increased risk for Covid 19 based on OR value: homozygous allele CC has 2.5(0.7-8.5), allele C with allele frequency 20 more than control group, and with OR=2.5(1.5-5.9) with significant P values (P=0.03).
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Background: In acute COVID-19 infection, growing evidence hints towards a broad activation of plasma cells and the presence of pathologic autoantibodies (abs). A systematic screening for abs confrmed induction of diverse functional abs by SARS-CoV-2 infection (1, 2). Immune-mediated thrombosis, involving platelet activation, has been identifed as one of the key pathogenic mechanisms in COVID-19 and is linked to morbidity and mortality (3). As natural abs against G protein-coupled receptors, functional abs against the thrombin receptor type-1 (PAR-1) might predispose for increased activation of the coagulation system present in COVID-19 infection. Objectives: The aim of this study is to identify the diagnostic value of anti-PAR1 antibodies and their capacity to predict the outcome of COVID-19 infection. Methods: 82 serum samples from 55 individuals with COVID-19 derived from three different hospitals in Schleswig-Holstein, Germany, and 88 single time point samples from healthy controls were subjected to ELISA-based quantifcation of anti-PAR-1 abs (CellTrend GmbH Luckenwalde, Germany). The levels of anti-AT1R abs were compared with clinical and laboratory parameters. Results: COVID-19 patients revealed markedly increased levels of circulating anti-PAR1 abs in hospitalized patients particularly in those required intensive care treatment in comparison to controls (p < 0.0001, Figure 1a). Anti-PAR1 ab levels were highest in patients with fatal outcome (p = 0.006, Figure 1a). Receiver operating characteristic (ROC) analysis of PAR1 abs levels in COVID-19 patients revealed a sensitivity of 84.00% and a specifcity 79.25% for patients requiring intensive care unit (ICU) treatment and a sensitivity of 87.50 % and a specifcity 84.51 % to distinguish fatal vs. non-fatal disease outcome (Figure 1b). We found correlation of circulating anti-PAR1 abs with D dimers. Conclusion: The increased anti-PAR1 abs, their prediction to identify patients requiring ICU and fatal outcome, and the correlation with markers for blood clotting suggest a role for antibodies against PAR1 in the disease development of blood clotting in COVID-19.
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Background: On January 30, 2020, the World Health Organization (WHO) declared the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, also called coronavirus disease 2019 (COVID-19) a pandemic after its emergence in Wuhan, China, in December 2019. In this study, we aimed to evaluate the potential of interleukin-6 (IL-6) and D-dimer serum levels and genotypes of rs5186 (A1166C) in the AGTR1 gene as potential prognostic markers for COVID-19 disease outcome in Iraq. Methods: This cross-sectional study was conducted with 100 Iraqi adults of both sexes, aged 21-81 years, and recently diagnosed with COVID-19. The participants of this study were admitted to Al-Al- Kindy Teaching Hospital and Ibn Al-Qiph in Baghdad City from February 01, 2020, to May 01, 2020. Patients with COVID-19 were divided into two categories;those who recovered and were discharged and those who were admitted to the intensive care unit (ICU)/died. Ethical concerns were considered in accordance with the consent form provided by the Iraqi Ministry of Health for the purpose of collecting samples. Interleukin-6 (IL-6) levels in the patients' serum samples were estimated using the Sandwich- Enzyme Linked Sorbent Assay (ELISA) method with horseradish peroxidase (HRP) conjugated antibody specific for IL-6. D-dimer was estimated in the serum samples using antigen-antibody (anti-human D-dimer antibodies) reaction. Genotyping of rs5186 (A1166C) in the AGTR1 angiotensin II receptor type 1 gene in the cohort study was determined using an allele-specific PCR approach. Results: D-dimer serum levels (1.55 μg/mL) was significantly (P < 0.001) higher in patients admitted to the ICU or those who died compared with those (0.2 mg/mL) of patients who recovered and were discharged. The IL-6 levels in patients admitted to the ICU or those who died and in patients who recovered and were discharged were 12.31 and 11.65 pg/mL, respectively, without significant difference (P > 0.05). The frequency of AC + CC genotypes of rs5186 (A1166C) in the AGTR1 gene in patients who were admitted to the ICU or those who died was 30.43%, higher than that of patients who recovered and were discharged (11.69%) with a significant difference (Odds ratio [OR] = 3.31, 95% confidence interval [CI] = 1.07-10.21, P = 0.038). Analysis of allele distribution revealed a higher frequency of the A allele among patients who recovered and were discharged (93.51% versus 82.61%) than among those who were admitted to the ICU or those who died with a significant difference (OR = 3.03, 95% CI = 1.12-8.21, P = 0.029). Conclusion: D-dimer may be a prognostic biomarker for poor COVID-19 disease outcomes. The genotype AC CC of rs5186 (A1166C) in the AGTR1 gene seems to be a risk factor and may be a prognostic factor for poor COVID-19 disease outcomes. However, a bigger sample size is highly recommended in prospective studies for better assessment of the potential of IL-6, D-dimer, and genotyping of rs5186 (A1166C) in the AGTR1 gene as prognostic biomarkers for COVID-19 disease outcome.
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Background: The aim of this study was to identify the cause of lymphopenia, strongly predictive of survival in COVID-19. Methods: We recruited PCR-positive SARS-CoV-2-infected patients upon admission to Intensive Care Units (ICU, n = 29) and to the Infectious Diseases Department (non-ICU, n = 29) at Nîmes University Hospital, as well as age-and sex-matched healthy controls (HC). Their Angiotensin II plasma levels were measured by ELISA and their monocytic reactive oxygen species (ROS) production and T-cell apoptosis were measured by flow cytometry using dichloro-dihydro-fluorescein diacetate and fluorescent annexin V, respectively. DNA damage and double strand breaks were quantified in immunofluorescence using antibodies specific for-γ-H2AX and 53BP1, respectively. Results: The monocytes of certain COVID-19 patients spontaneously released ROS able to induce DNA damage and apoptosis in neighboring cells. High ROS production was predictive of death. Indeed, in most patients we observed the presence of DNA damage in up to 50% of their peripheral mononuclear blood cells, with double-strand DNA breaks, and T-cell apoptosis. The intensity of this DNA damage was linked to lymphopenia. SARS-CoV-2 is known to induce the internalization of its receptor, Angiotensin Converting Enzyme 2, a protease able to catabolize Angiotensin II. Accordingly, we observed high plasma levels of Angiotensin II in ROS-producing patients. In search of the stimulus responsible for their ability to release ROS, we unveiled that Angiotensin II triggers ROS production by monocytes via Angiotensin receptor I (AT1). ROS released by Angiotensin II-activated monocytes induced DNA damage and apoptosis in neighboring cells. Conclusion: Mononuclear cell apoptosis provoked via DNA damage due to the release of monocytic ROS could play a major role in COVID-19 pathogenesis, inasmuch as ROS are also known to trigger inflammatory cytokine production. Unveiling this new pathogenic pathway opens up new therapeutic possibilities for COVID-19 based on the early association of AT1 antagonists and antioxidants.
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Introduction: ACE inhibitor (ACEI) or angiotensin receptor blocker (ARB) use in COVID-19 raised concern due to reported increases in ACE2, the cell receptor for SARS-CoV2. We tested the hypothesis that ARB (Losartan) and ACEI (Captopril) do not impact SARS-CoV2 associated ACE2 expression in cardiomyocytes (CMs). Methods: Beating monolayer ventricular CMs were generated from human iPSCs and grown as engineered heart tissue constructs (EHTs), which mimic a more mature phenotype than monolayer CMs. Drug treatments (24hrs) without pseudovirus were applied to EHTs: (A) Vehicle, 1μM Losartan (ARB), 1μM Angiotensin II (AngII), 1μM Losartan+1μM Ang II;(B) Vehicle, 1μM Captopril, 1μM Ang I, or 1μM AngI+1μM Captopril with 2-3 replicates for each combination and RNAseq as outcome. Drug treatment A only was repeated in monolayer CMs with a 5-6 day to rVSV-SARS-Cov2SpikeLuciferase-FLAG tagged pseudovirus (2-4 replicates) with immunoblotting for ACE2, Cathepsin B (CTSB) and Furin proteins. Results: Immunoblot densitometry showed abundant ACE2 protein in untreated CMs and EHTs. A focused mRNA analysis of 12 genes associated with SARS-Cov2 entry and processing (EHTs) revealed no significant changes in expression of ACE2, NRP1, CTSB, CTSL and FURIN due to Losartan or Captopril treatment. There was a nonsignificant trend towards Losartan-induced increase in AGTR1 with attenuation when AngII was administered, while ITGA5 trended upwards with Losartan+AngII. AGTRI also trended upwards with Captopril and AngI+Captopril. Upon pseudoviral challenge, CMs demonstrated increased ACE2 (55%) and slightly decreased Furin (24%) protein, with unchanged CTSB, although results were not statistically significant. Losartan addition, regardless of AngII, did not alter SARS-CoV2Spike pseudovirus mediated changes of ACE2, Furin or CTSB proteins. Conclusions: Losartan or Captopril did not substantially alter gene expression of ACE2, CTSB, CTSL, FURIN and NRP1 in EHTs without pseudovirus. Losartan did not show convincing evidence for pseudoviral mediated changes of proteins important for viral entry and processing in CM cell models.