Covid-19, Coronavirus, SARS-CoV-2 and the small bowel

Although SARS-CoV-2 may primarily enter the cells of the lungs, the small bowel may also be an important entry or interaction site...

ABSTRACT – Although SARS-CoV-2 may primarily enter the cells of the lungs, the small bowel may also be an important entry or interaction site, as the enterocytes are rich in angiotensin converting enzyme (ACE)-2 receptors. The initial gastro- intestinal symptoms that appear early during the course of Covid-19 support this hypothesis. Furthermore, SARS- CoV virions are preferentially released apically and not at the basement of the airway cells. Thus, in the setting of a productive infection of conducting airway epithelia, the apically released SARS-CoV may be removed by mucocil- iary clearance and gain access to the GI tract via a luminal exposure. In addition, post-mortem studies of mice infected by SARS-CoV have demonstrated diffuse damage to the GI tract, with the small bowel showing signs of enterocyte desquamation, edema, small vessel dilation and lympho- cyte infiltration, as well as mesenteric nodes with severe hemorrhage and necrosis. Finally, the small bowel is rich in furin, a serine protease which can separate the S-spike of the coronavirus into two “pinchers” (S1 and 2).The sep- aration of the S-spike into S1 and S2 is essential for the attachment of the virion to both the ACE receptor and the cell membrane. In this special review, we describe the inter- action of SARS-CoV-2 with the cell and enterocyte and its potential clinical implications.

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