Effects of Bile Acid Modulation by Dietary Fat, Cholecystectomy, and Bile Acid Sequestrant on Energy, Glucose, and Lipid Metabolism and Gut Microbiota in Mice

Abstract

Bile acid metabolism, involved with the digestion and absorption of nutrients in the gut, is linked to the gut microbiota community, greatly impacting the host’s metabolism. We examined the hypothesis that the modulation of bile acid metabolism by dietary fat contents, gallbladder removal (GBX; cholecystectomy), and bile acid sequestrant (BAS; cholestyramine) treatment could alter energy, glucose, and lipid metabolism through the changes in the gut microbiota. Mice were randomly assigned to the following six groups: (1) Sham GBX surgery (Sham) + low fat/high carbohydrate diet (LFD), (2) Sham + high fat diet (HFD), (3) Sham + HFD + BAS, (4) GBX + LFD, (5) GBX + HFD, and (6) GBX + HFD + BAS. BAS groups received 2% cholestyramine. After an 8-week intervention, energy, glucose, and lipid metabolism, and the gut microbiota community were measured. HFD groups exhibited higher body weight gain than LFD, and GBX increased the weight gain comped to Sham groups regardless of BAS in HFD (p < 0.05). Homeostatic model assessment for insulin resistance (HOMA-IR) was higher in HFD than LFD, and GBX increased it regardless of BAS. Serum lipid profiles were worsened in GBX + HFD compared to Sham + LFD, whereas BAS alleviated them, except for serum HDL cholesterol. Hepatic tumor-necrosis-factor-α (TNF-α) mRNA expression and lipid peroxide contents increased with GBX and BAS treatment compared to Sham and no BAS treatment (p < 0.05). Hepatic mRNA expression of sterol regulatory element-binding transcription factor 1c (SREBP1c) and peroxisome proliferator-activated receptor gamma (PPAR-γ) exhibited the same trend as that of tumor necrosis factor-α (TNF-α). The α-diversity of gut bacteria decreased in GBX + HFD and increased in GBX + HFD + BAS. Akkermentia, Dehalobacterium, SMB53, and Megamonas were high in the Sham + LFD, and Veillonella and Streptococcus were rich in the Sham + HFD, while Oscillospira and Olsenella were high in Sham + HFD + BAS (p < 0.05). GBX + LFD increased Lactobacillus and Sutterella while GBX + HFD + BAS elevated Clostridium, Alistipes, Blautia, Eubacterium, and Coprobacillus (p < 0.05). In conclusion, the modulation of bile acid metabolism influences energy, glucose, and lipid metabolisms, and it might be linked to changes in the gut microbiota by bile acid metabolism modulation.

Modulation of the Gut Microbiota in Memory Impairment and Alzheimer’s Disease via the Inhibition of the Parasympathetic Nervous System

“…The suppression of the PNS by scopolamine in MD group decreased Bacteroides and increased Clostridium, Lactobacillus , and Escherichia, compared to the normal group in the present animal study. Previous studies have demonstrated that a high-fat diet increases Bacteroidaceae, compared to a low-fat diet in rats with intact gallbladders, but does not do so in rats without gallbladders [ 19 ]. It suggests that bile acid is responsible for the increased Bacteroidaceae.…”

“…It suggests that bile acid is responsible for the increased Bacteroidaceae. The PNS inhibition suppresses the bile acid synthesis and secretion, which may change the gut microbiota in a high-fat diet [ 19 , 20 ]. In the present study, the reduced Bacteroidaceae in the scopolamine-injected rats, was related to inhibiting the bile acid secretion by the suppressed PNS.…”

Alleviation of Metabolic Disturbance by Substituting Kanjang High in Bacillus for Salt through Modulation of Gut Microbiota in Estrogen-Deficient Rats

“…The separation of each group in β-diversity was analyzed using the permutation-based variance analysis (PER-MANOVA). Network analysis determined the links among gut bacteria at the genus level, SCFA, visceral fat mass, and glucose metabolism were determined [27].…”

Mitigation of Memory Impairment with Fermented Fucoidan and λ-Carrageenan Supplementation through Modulating the Gut Microbiota and Their Metagenome Function in Hippocampal Amyloid-β Infused Rats

“…They contribute to cognitive function [ 14 ]. Dietary fiber also modulates the gut microbiota community to change bile acid reabsorption and metabolism, potentially influencing the host metabolism and brain function through the gut-brain axis [ 14 , 15 ].…”