The protective potential of intestinal Bifidobacterium-derived extracellular vesicles with unique lipid composition against blue light-induced damage in retinal cells.

Bifidobacterium longum is a probiotic that resides in the intestine, and extracellular vesicles (EVs) released by microorganisms have garnered attention in recent years for their role in regulating host health. This study found that triacylglycerol, cholesteryl esters, and free fatty acid (18:0 and 16:0) are primarily composed of lipids in B. longum-derived EVs by lipidomics assay. Such lipid composition facilitates the entry of EVs into ARPE-19 cells and protects the cells from oxidative death induced by blue light exposure. Transcriptomic analysis revealed that treatment with B. longum-derived EVs can regulate phosphoinositide 3-kinase and mTOR, thereby enhancing the survival capacity of blue light-induced ARPE-19 cells. Intestinal microbiota is strongly associated with host disease, and this study provides a strategy suggesting that intestinal probiotic EVs might potentially be used in the future to protect eyes from damage caused by blue light sensitivity through the gut-eye axis.