Fig. 1.

Gut metabolites–immune system crosstalk in stroke. Immune system regulation by the gut microbiome after stroke. Lower panel: In the gut, stroke induces dysbiosis, mucosal barrier dysfunction, an increase of gut permeability, bacteria translocation, post-stroke infection, and a pro-inflammatory T-cell response via dendritic cells (DC). Immune cells, especially T-cells, CD64 + macrophages and DCs migrate from the gut to the meninges and the brain after stroke. The role of gut metabolites (AHR, secondary bile acids, MAMPs) as immunomodulators of intestinal immune cells is not well defined yet. Microbiota-derived SCFA are decreased after stroke and possibly trigger an imbalance of γδT-IL-17 + cells and regulatory T-cells (Treg). Top panel: Supplementation of SCFA modulates neuronal activity and synapse density, and is associated with a decrease in microglia activation and an increase in Tregs together with a better recovery after stroke. Created with BioRender.com