Fig. 12
From: Pathophysiology of Post-COVID syndromes: a new perspective
Role of mast cell activation syndrome in the development of Post-COVID syndrome: Stressful conditions during SARS-CoV-2 infection increase the release of corticotropic releasing factor (CRF), adrenocorticotropic hormone (ACTH), and cortisol. Besides, gut stress induces alteration of the gut microbiota, which affects the release of neurotransmitters, tryptophan metabolism, and the release of short-chain free fatty acids (SCFAs). These changes induce activation of mast cells, which releases inflammatory cytokines. Thus, mast cells link the brain and gut through neuronal, immune, and endocrine pathways