ABSTRACT
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.
ABSTRACT
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (COVID-19), has led to an unprecedented public health emergency worldwide. While common cold symptoms are observed in mild cases, COVID-19 is accompanied by multiorgan failure in severe patients. Organ damage in COVID-19 patients is partially associated with the indirect effects of SARS-CoV-2 infection (e.g., systemic inflammation, hypoxic-ischemic damage, coagulopathy), but early processes in COVID-19 patients that trigger a chain of indirect effects are connected with the direct infection of cells by the virus. To understand the virus transmission routes and the reasons for the wide-spectrum of complications and severe outcomes of COVID-19, it is important to identify the cells targeted by SARS-CoV-2. This review summarizes the major steps of investigation and the most recent findings regarding SARS-CoV-2 cellular tropism and the possible connection between the early stages of infection and multiorgan failure in COVID-19. The SARS-CoV-2 pandemic is the first epidemic in which data extracted from single-cell RNA-seq (scRNA-seq) gene expression data sets have been widely used to predict cellular tropism. The analysis presented here indicates that the SARS-CoV-2 cellular tropism predictions are accurate enough for estimating the potential susceptibility of different cells to SARS-CoV-2 infection; however, it appears that not all susceptible cells may be infected in patients with COVID-19.
ABSTRACT
The virulence of avian gamma-coronavirus infectious bronchitis viruses (IBV) for the kidney has led to high mortality in dominant-genotype isolations, but the key sites of viral protein that determine kidney tropism are still not fully clear. In this study, the amino acid sequences of the S2 subunit of IBVs with opposing adaptivity to chicken embryonic kidney cells (CEKs) were aligned to identify putative sites associated with differences in viral adaptability. The S2 gene and the putative sites of the non-adapted CN strain were introduced into the CEKs-adapted SczyC30 strain to rescue seven mutants. Analysis of growth characteristics showed that the replacement of the entire S2 subunit and the L1089I substitution in the S2 subunit entirely abolished the proliferation of recombinant IBV in CEKs as well as in primary chicken oviduct epithelial cells. Pathogenicity assays also support the decisive role of this L1089 for viral nephrotropism, and this non-nephrotropic L1089I substitution significantly attenuates pathogenicity. Analysis of the putative cause of proliferation inhibition in CEKs suggests that the L1089I substitution affects neither virus attachment nor endocytosis, but instead fails to form double-membrane vesicles to initiate the viral replication and translation. Position 1089 of the IBV S2 subunit is conservative and predicted to lie in heptad repeat 2 domains. It is therefore reasonable to conclude that the L1089I substitution alters the nephrotropism of parent strain by affecting virus-cell fusion. These findings provide crucial insights into the adaptive mechanisms of IBV and have applications in the development of vaccines and drugs against IB.
Subject(s)
Coronavirus Infections , Infectious bronchitis virus , Poultry Diseases , Chick Embryo , Animals , Cell Fusion/veterinary , Chickens , Viral Tropism , Kidney , Tropism , Coronavirus Infections/veterinary , Spike Glycoprotein, Coronavirus/geneticsABSTRACT
The emerging coronavirus called SARS-CoV-2 has spread rapidly around the world. Responsible for severe pneumonitis (Covid-19), there are also doubts concerning a possible mother-to-fetal transmission of this virus. Current data are patchy and obtained from small groups of patients. They tend to support the idea that the mother-to-fetal transmission of SARS-CoV-2 is very rare, but the period between infection and childbirth was often very short and may not allow sufficient replication to consider transplacental passage. Here, we reviewed the existing virological data and those remaining to explore. Thus, the natural history of SARS-CoV-2 infection in pregnant women and the risk of transmission in utero is not yet fully understood and defined. Four months from the emergence of this virus, it is therefore reasonable to wait for the results of specific studies on larger cohorts which, to be conclusive, must meet the best scientific criteria.