Fig. 2
From: Gut microbiota as the key controllers of “healthy” aging of elderly people
Commensal microbes are sole producers of beneficial SCFAs. 1, In the gut of healthy young people, beneficial commensal bacterial members of Firmicutes produce SCFAs. 2, SCFAs provide energy to the microbiota and 3, thereby can inhibit the colonization of opportunistic bacteria; and 4, promote the production of protective mucus. 5, SCFAs are also source of energy for enterocytes and 6, immune cells. They can cross the gut epithelium layer to promote immune tolerance by 7, inducing TGFβ producing FoxP3+ regulatory T cells (Tregs), 8, IL-10 producing T cells; 9, activating anti-inflammatory responses in antigen presenting cells (APCs); and 10, promoting the production of IgA and IgG from B cells. 11, SCFAs also initiate anti-inflammatory responses in neutrophils and 12, affect their recruitment