posted on 2024-02-23, 04:30authored byXiaojin Yuan, Juan Liu, Chenxi Nie, Qingyu Ma, Chaoqi Wang, Huicui Liu, Zhifei Chen, Min Zhang, Juxiu Li
Nε-carboxymethyllysine (CML)
is produced by a nonenzymatic
reaction between reducing sugar and ε-amino group of lysine
in food and exists as free and bound forms with varying digestibility
and absorption properties in vivo, causing diverse
interactions with gut microbiota. The effects of different forms of
dietary CML on the gut microbiota and intestinal barrier of mice were
explored. Mice were exposed to free and bound CML for 12 weeks, and
colonic morphology, gut microbiota, fecal short-chain fatty acids
(SCFAs), intestinal barrier, and receptor for AGE (RAGE) signaling
cascades were measured. The results indicated that dietary-free CML
increased the relative abundance of SCFA-producing genera including Blautia, Faecalibacterium, Agathobacter, and Roseburia. In contrast, dietary-bound CML
mainly increased the relative abundance of Akkermansia. Moreover, dietary-free and -bound CML promoted the gene and protein
expression of zonula occludens-1 and claudin-1. Additionally, the
intake of free and bound CML caused an upregulation of RAGE expression
but did not activate downstream inflammatory pathways due to the upregulation
of oligosaccharyl transferase complex protein 48 (AGER1) expression,
indicating a delicate balance between protective and proinflammatory
effects in vivo. Dietary-free and -bound CML could
modulate the gut microbiota community and increase tight-junction
expression, and dietary-free CML might exert a higher potential benefit
on gut microbiota and SCFAs than dietary-bound CML.