In vitro fermentation mediated by Akkermansia muciniphila caused lactate accumulation and blocked butyrate production via shaping functional bacterial community

To investigate the effect of Akkermansia muciniphila on hypertension, the study performed an in vitro fermentation on the feces of hypertensive patients. The experimental groups were hypertensive elderly (E), hypertensive elderly + A. muciniphila (EA), and hypertensive long-lived elderly (L). Results showed that the pH value decreased among the 3 groups and produced numerous lactate at 9 h. Then, the pH value increased and lactate was almost exhausted at 48 h in group E. However, compared to groups E and L, group EA showed lower pH value, lower butyrate level, and higher lactate level. Compared to group E in 9 h, EA significantly increased the relative abundance of Akkermansia and Lactococcus and decreased Clostridium_sensu_stricto_1. The relative abundances of Akkermansia and Bifidobacterium increased in the group EA compared to group E, whereas the relative abundances of Clostridium_sensu_stricto_1 decreased at 48 h. Metabolomics showed that A. muciniphila altered the levels of 9 metabolites with reduced trimethylamine (TMA) and trimethyl-5-aminovaleric acid (TMAVA) related to hypertension. The lactate concentration showed positive correlation with Enterococcus and Bifidobacterium, and the butyrate concentration showed positive correlation with Clostridium_sensu_stricto_1, indicating that metabolites shifts by those functional bacterial communities. These results present a potential perspective for A. muciniphila mediated microbial micro-environment change to increase the relative abundance of Bifidobacterium and lactate production.