Enterococcus faecium R-026 combined with Bacillus subtilis R-179 alleviate hypercholesterolemia and modulate the gut microbiota in C57BL/6 mice

Abstract Probiotics have been demonstrated to lower total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) in individuals with mild hypercholesterolemia. Our previous study found that intervention with Bacillus subtilis R-179 and Enterococcus faecium R-026, well-known probiotics, improved obesity-associated dyslipidemia through ameliorating the gut microbiota, but similar studies on hypercholesterolemia have not been reported to date. Here, we investigated the therapeutic effect of live combined B. subtilis R-179 and E. faecium R-026 (LCBE) in a C57BL/6 mouse model of hypercholesterolemia. A total of 40 mice were administered with a high-cholesterol diet (containing 1.2% cholesterol) to establish a state of hypercholesterolemia for 4 weeks. Then, mice were divided into one model group (group M) and three treatment groups (n = 10 per group), which were administered with LCBE at 0.023 g/mouse/day (group L) or 0.230 g/mouse/day (group H), or atorvastatin 0.010 g/kg/day (group A), for 5 weeks while on a high-cholesterol diet. LCBE at high doses significantly alleviated the symptoms of group M and reduced serum TC, LDL-C, and lipopolysaccharide (LPS). LCBE improved liver steatosis and adipocyte enlargement caused by a high-cholesterol diet. In addition, the administration of LCBE regulated the change in gut microbiota and diversity (Shannon index). Compared with group M, the relative abundance of Actinobacteriota, Colidextribacter, and Dubosiella dramatically decreased in the treatment groups, which were positively correlated with serum TC and LPS. These findings indicated that the mechanism of action of LCBE in treating hypercholesterolemia may be modulation of the gut microbiota. In conclusion, LCBE ameliorated lipid accumulation, reduced inflammation, and alleviated the gut microbiota imbalance in hypercholesterolemic mice. These findings support the probiotic role of LCBE as a clinical candidate for the treatment of hypercholesterolemia.