COVID-19, coronavirus, SARS-CoV-2 and the small bowel

Area of Science:

• Virology
• Gastroenterology
• Cell Biology

Background:

• Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) primarily infects lung cells.
• Enterocytes, the cells lining the small intestine, are abundant in angiotensin-converting enzyme (ACE)-2 receptors, a key binding site for SARS-CoV-2.
• Gastrointestinal symptoms are frequently observed in early stages of COVID-19, suggesting a potential role for the GI tract in infection.

Purpose of the Study:

• To explore the interaction of SARS-CoV-2 with enterocytes.
• To investigate the small bowel as a potential site for SARS-CoV-2 entry and replication.
• To discuss the clinical implications of SARS-CoV-2 interaction with the gastrointestinal tract.

Main Methods:

• Review of existing literature on SARS-CoV-2 cell entry mechanisms.
• Analysis of post-mortem studies on SARS-CoV infected mice, focusing on GI tract pathology.
• Examination of the role of ACE-2 receptors and furin in viral entry and S-spike protein activation.

Main Results:

• Enterocytes express ACE-2 receptors, facilitating SARS-CoV-2 binding and entry.
• Apical release of SARS-CoV from airway epithelia may lead to GI tract exposure via mucociliary clearance.
• Post-mortem studies reveal significant GI tract damage in SARS-CoV infected mice, including enterocyte desquamation and mesenteric lymph node necrosis.

Conclusions:

• The small bowel is a potential site for SARS-CoV-2 entry and interaction due to ACE-2 receptor expression.
• Viral entry into enterocytes is facilitated by ACE-2 receptors and furin-mediated S-spike protein cleavage.
• Understanding SARS-CoV-2's interaction with the GI tract is crucial for comprehending its clinical manifestations and transmission.