Is Gut Involvement a Cause or Effect of COVID-19?

Area of Science:

• Gastroenterology
• Virology
• Infectious Diseases

Background:

• Digestive symptoms in COVID-19 patients can mimic post-infectious functional gastrointestinal disorder (PI-FGID).
• The severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) requires intestinal transit for clinical effects, potentially facilitated by gastric hypochlorhydria.
• Asian elderly populations exhibit higher COVID-19 infection rates and severity, possibly due to prevalent gastric atrophy and proton-pump inhibitor use.

Purpose of the Study:

• To explore the gastrointestinal manifestations of COVID-19.
• To investigate the role of the angiotensin-converting enzyme 2 (ACE2) receptor in SARS-CoV-2 gut involvement.
• To examine the implications of gut microbiota dysregulation and inflammatory responses in COVID-19 pathogenesis.

Main Methods:

• Review of existing literature on COVID-19 and gastrointestinal symptoms.
• Analysis of the mechanism of SARS-CoV-2 entry into the gastrointestinal tract via ACE2 receptors.
• Examination of factors predisposing specific populations, like the Asian elderly, to severe outcomes.

Main Results:

• SARS-CoV-2 utilizes the ACE2 receptor for entry into the small bowel, impacting gut microbiota homeostasis and inflammation.
• Persistence of SARS-CoV-2 in stool suggests fecal transmission is a potential route.
• Liver injury in COVID-19 is often a secondary effect, not a direct viral process.

Conclusions:

• Gut involvement in COVID-19 is significant, with potential links to PI-FGID and specific demographic risks.
• ACE2 receptor dysregulation plays a crucial role in the gut's response to SARS-CoV-2.
• Further research is essential to elucidate the causal relationship between gut involvement and SARS-CoV-2 infection.