Digestive Manifestations of Post-COVID-19: A Focus on Therapeutic Strategies

Abstract

Post-COVID-19 is a chronic infection-related syndrome, including exacerbations of pre-existing or newly diagnosed conditions that have been established after the acute phase of COVID-19 and have demonstrated a wide range of systemic effects beyond the lungs. SARS-CoV-2 attaches to its receptor, angiotensin-converting enzyme 2 (ACE-2). Transmembrane serine protease 2 (TMPRSS2) facilitates viral entry and spread. ACE-2 receptors are detectable in several tissues, including the respiratory mucosa, digestive tract, heart, kidney, and brain. Several investigations have demonstrated an increase in digestive manifestations post-acute COVID-19, likely related to an alteration in the intestinal microbiota following infection. These changes can lead to a loss of species diversity, resulting in an overgrowth of opportunistic pathogens and deprivation of commensal bacteria. In this context, post-infection irritable bowel syndrome shows an increased incidence compared to controls. Growing evidence also suggests the enduring presence of SARS-CoV-2 in the gut tissue. Studies are ongoing to investigate antiviral agents that counteract prolonged COVID-19 symptoms. Therefore, the objectives of this review were to summarize the digestive manifestations, focusing on irritable bowel syndrome and therapeutic strategies. This review gives an overview of studies published in English in the last two years on the PubMed database.

Keywords: COVID-19; SARS-CoV-2; antiviral agents; digestive manifestations; irritable bowel syndrome; post-COVID-19; probiotics; therapeutic strategies.

Figure 1

Proposed pathophysiological mechanisms of post-COVID-19 irritable bowel syndrome. Legend: SARS-CoV-2 binds to ACE-2 receptors present in enterocytes of the ileum and large intestine, influencing the function of intestinal absorption of dietary amino acids, such as tryptophan, and the secretion of antimicrobial peptides. In the intestine, the virus alters the composition of the microbiota. Downregulation of receptors increases the gene expression of several inflammatory cytokines that induce epithelial and barrier damage. Viral persistence and immune and microbiota alterations can affect motility and visceral perception by neurotransmitters, leading to a systemic alteration in brain functions through the gut microbiota–immune–brain axis, resulting in post-COVID-19 irritable bowel syndrome-like symptoms among post-COVID-19 syndrome (within 3 months), confirming post-COVID-19 irritable bowel syndrome with a minimum of 6 months of symptom onset.