Alteration of gut microbiota in association with cholesterol gallstone formation in mice

Berberine alleviates cholesterol and bile acid metabolism disorders induced by high cholesterol diet in mice

Berberine (BBR) is a traditional Chinese herb with broad antimicrobial activity. Gut microbiota plays an important role in the metabolism of bile acids and cholesterol. Our study investigated the effects of BBR on alleviating cholesterol and bile acid metabolism disorders induced by high cholesterol diet in mice. Adult male C57BL/6J mice fed with high cholesterol diet (HC) containing 1.25 % cholesterol (HC group) or fed with chow diet containing 0.02 % cholesterol (Chow group) served as controls. BBR50 and BBR100 group mice were fed with HC, and oral BBR daily at doses of 50 or 100 mg/kg respectively for 8 weeks. The results showed that BBR could reshape the homeostasis and composition of gut microbiota. The abundance of Clostridium genera was significantly inhibited by BBR, which resulted in a significant reduction of secondary bile acids within the enterohepatic circulation and a significant lower hydrophobic index of bile acids. The absorption of cholesterol in intestine, the deposition of cholesterol in liver and the excretion of cholesterol in biliary tract were significantly inhibited by BBR, which promoted the unsaturation of cholesterol in bile. These findings suggest the potential utility of BBR as a functional food to alleviate the negative effects of high cholesterol diet.

Relationship between triglyceride-glucose index and gallstones risk: a population-based study

Background

Globally, gallstones represented a prevalent condition of the digestive system, heavily affected by metabolic dysfunctions such as obesity, dyslipidemia, insulin resistance, and diabetes. The triglyceride-glucose (TyG) index served as an accessible novel indicator for evaluating insulin resistance, offering a precise reflection of metabolic conditions. However, no studies have yet explored their relationship. The link between the TyG and gallstone risk was the primary purpose of this study.

Methods

Utilized data from the public database, the National Health and Nutrition Examination Survey, for the years 2017-2020. The logit model was utilized to elucidate the connection between the TyG and the gallstones risk. The restricted cubic spline (RCS) analysis served to verify any non-linear relationships existing between them. Sensitivity analyses, encompassing both stratified and interaction analyses, were conducted to identify populations of particular interest and assess potential interactions between covariates and the TyG index.

Results

A total of 4544 individuals were included. The risk of gallstones in high group was 1.6 times that of the low group. The potential cut-off value for the TyG index was 6.19. Above this threshold, there was a 40% heightened risk of gallstones with each one-unit increment in the TyG. The RCS analysis revealed the absence of a non-linear association between them. The populations warranting particular focus included those over 60 years, non-White people, individuals with a body mass index ≥25, smokers, drinkers, those with hypertension, and diabetes. Apart from smoking history, alcohol consumption, and history of diabetes, there were no interactions between other variables and the TyG index.

Conclusion

The current study represented the inaugural investigation into the link between TyG index and the risk of gallstones. A positive correlation existed between them, signifying that an increase in TyG paralleled an elevated risk of gallstones. No non-linear relationship has been found between them. Besides, a 40% increase in gallstone risk accompanied each unit rise in TyG. Considering the convenience and accessibility of TyG in clinical settings, it has a promising potential for clinical application.

Comprehensive analysis of differential long non-coding RNA and messenger RNA expression in cholelithiasis using high-throughput sequencing and bioinformatics

Background

The etiology of gallstone disease (GSD) has not been fully elucidated. Consequently, the primary objective of this study was to scrutinize and provisionally authenticate the distinctive expression profiles of long non-coding RNAs (lncRNAs) and messenger RNAs (mRNAs) in GSD.

Methods

RiboNucleic Acid (RNA) sequencing was used on four paired human gallbladder samples for the purpose of this study. Differentially expressed lncRNAs (DElncRNAs) and mRNAs (DEmRNAs) were identified and subjected to analysis of their biological functions. The Pearson's correlation coefficients between DElncRNAs and DEmRNAs were computed to construct a co-expression network delineating their associations. Furthermore, both cis- and trans-regulatory networks of selected lncRNAs were established and visualized. Additionally, a competing endogenous RNA (ceRNA) regulatory network was constructed. To validate the RNA-sequencing data, we performed a Quantitative Real-time Polymerase Chain Reaction (RT-qPCR) on 10 paired human gallbladder samples, assessing the expressions of the top 4 DEmRNAs and DElncRNAs in gallstone and control samples.

Results

A total of 934 DEmRNAs and 304DElncRNAs were successfully identified. Functional enrichment analysis indicated a predominant involvement in metabolic-related biological functions. Correlation analysis revealed a strong association between the expressions of 597 DEmRNAs and 194 DElncRNAs. Subsequently, both a cis-lncRNA-mRNA and a trans-lncRNA-Transcription Factor (TF)-mRNA regulatory network were meticulously constructed. Additionally, a ceRNA network, comprising of 24 DElncRNAs, 201 DEmRNAs, and 120 predicted miRNAs, was established. Furthermore, using RT-qPCR, we observed significant upregulation of AC004692.4, HECW1-IT1, SFRP4, and COMP, while LINC01564, SLC26A3, RP1-27K12.2, and GSTA2 exhibited marked downregulation in gallstone samples. Importantly, these findings were consistent with the sequencing.

Conclusion

We conducted a screening process to identify DElncRNAs and DEmRNAs in GSD. This approach contributes to a deeper understanding of the genetic factors involved in the etiology of gallstones.

Microplastics are detected in human gallstones and have the ability to form large cholesterol-microplastic heteroaggregates

Ubiquitous pollution due to microplastics through the food chain is a major cause of various deleterious effects on the human health. The aim of this study was to determine the existence of microplastics and the internal mechanism of microplastics as accelerators of cholelithiasis. Gallstones were collected from 16 patients after cholecystectomy, and microplastics in the gallstones were detected through laser direct infrared and pyrolysis gas chromatographymass spectrometry examinations. Mice model of gallstone were constructed with or without different diameters of microplastic (0.5, 5 and 50 µm). The affinity between microplastic and cholesterol or bilirubin was tested by co-culturing and qualified using molecular dynamics simulations. Finally, altered gut microbiota among the groups were identified using 16 s rRNA sequencing. The presence of microplastics in the gallstones of all the patients were confirmed. Microplastic content was significantly higher in younger chololithiasis patients (age<50 years). Mice fed a high-cholesterol diet with microplastic drinks showed more severe chololithiasis. In terms of the mechanism, microplastics showed a higher affinity for cholesterol than for bilirubin. Significant alterations in the gut microbiota have also been identified after microplastic intake in mice. Our study revealed the presence of microplastics in human gallstones, showcasing their potential to aggravate chololithiasis by forming large cholesterol-microplastic heteroaggregates and altering the gut microbiota.

Intestinal microbiota and biliary system diseases

Introduction

The incidence of biliary system diseases has been continuously increasing in the past decade. Biliary system diseases bring a heavy burden to humanity and society. However, the specific etiology and pathogenesis are still unknown. The biliary system, as a bridge between the liver and intestine, plays an indispensable role in maintaining the physiological metabolism of the body. Therefore, prevention and treatment of biliary diseases are crucial. It is worth noting that the microorganisms participate in the lipid metabolism of the bile duct, especially the largest proportion of intestinal bacteria.

Methods

We systematically reviewed the intestinal microbiota in patients with gallstones (GS), non-calculous biliary inflammatory, and biliary tract cancer (BTC). And searched Pubmed, Embase and Web of science for research studies published up to November 2023.

Results

We found that the abundance of Faecalibacterium genus is decreased in GS, primary sclerosing cholangitis (PSC), primary biliary cholangitis (PBC) and BTC. Veillonella, Lactobacillus, Streptococcus and Enterococcus genus were significantly increased in PSC, PBC and BTC. Interestingly, we found that the relative abundance of Clostridium was generally reduced in GS, PBC and BTC. However, Clostridium was generally increased in PSC.

Discussion

The existing research mostly focuses on exploring the mechanisms of bacteria targeting a single disease. Lacking comparison of multiple diseases and changes in bacteria during the disease process. We hope to provide biomarkers forearly diagnosis of biliary system diseases and provide new directions for the mechanism of intestinal microbiota in biliary diseases.

The role of bacteria in gallstone formation

Gallstones are a prevalent biliary system disorder that is particularly common in women. They can lead to various complications, such as biliary colic, infection, cholecystitis, and even gallbladder cancer. However, the etiology of gallstones remains incompletely understood. The significant role of bacteria in gallstone formation has been demonstrated in recent studies. Certain bacteria not only influence bile composition and the gallbladder environment but also actively participate in stone formation by producing enzymes such as β-glucuronidase and mucus. Therefore, this review aimed to analyze the mechanisms involving the types and quantities of bacteria involved in gallstone formation, providing valuable references for understanding the etiology and clinical treatment of gallstones.

Ganoderma lucidum polysaccharide ameliorates cholesterol gallstone formation by modulating cholesterol and bile acid metabolism in an FXR-dependent manner

BACKGROUND

Cholesterol gallstone (CG) disease is a worldwide common disease characterized by cholesterol supersaturation in gallbladder bile. Ganoderma lucidum polysaccharide (GLP) has been shown to possess various beneficial effects against metabolic disorders. However, the role and underlying mechanism of GLP in CG formation are still unknown. This study aimed to determine the role of GLP in ameliorating lithogenic diet (LD)-induced CG formation.

METHODS

Mice were fed either a normal chow diet, a LD, or LD supplemented with GLP. Real-time quantitative polymerase chain reaction (RT-qPCR) and western blotting were used to detect the expression of genes involved in cholesterol and bile acid (BA) metabolism. The BA concentrations in the ileum were quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The microbiota in cecal contents were characterized using 16S ribosomal RNA (16S rRNA) gene sequencing.

RESULTS

GLP effectively alleviated CG formation induced by LD. Specifically, GLP reduced the total cholesterol (TC) levels, increased the total BA levels, and decreased the cholesterol saturation index (CSI) in gallbladder bile. The protective effect of GLP was attributed to the inhibition of farnesoid X receptor (FXR) signaling, increased hepatic BA synthesis and decreased hepatic cholesterol synthesis and secretion. GLP also altered the BA composition in the ileum, reducing FXR-agonistic BAs and increasing FXR-antagonistic BAs, which may contribute to the inhibition of intestinal FXR signaling. Additionally, GLP improved dysbiosis of the intestinal flora and reduced the serum levels of hydrogen sulfide (H2S), a bacterial metabolite that can induce hepatic FXR, thereby inhibiting hepatic FXR signaling. Moreover, the protective effect of GLP against CG formation could be reversed by both the global and gut-restricted FXR agonists.

CONCLUSIONS

Taken together, GLP ameliorates CG formation by regulating cholesterol and BA metabolism in an FXR-dependent manner. Our study demonstrates that GLP may be a potential strategy for the prevention against CG disease.

Profiles of biliary microbiota in biliary obstruction patients with Clonorchis sinensis infection

Background

Clonorchis sinensis (C. sinensis) is a epidemiologically significant food-borne parasite, causing several hepatobiliary diseases. Biliary microbiota community structure might be influenced by infection with pathogens. However, the biliary microbiome of biliary obstruction patients infected with C. sinensis is still an unexplored aspect.

Methods

A total of 50 biliary obstruction patients were enrolled, including 24 infected with C. sinensis and 26 non-infected subjects. The bile samples were collected by Endoscopic Retrograde Cholangiopancretography. Biliary microbiota alteration was analyzed through high-throughput 16S ribosomal RNA (rRNA) gene sequencing.

Results

Our findings revealed that there was significant increase in both richness and diversity, as well as changes in the taxonomic composition of the biliary microbiota of C. sinensis infected patients. At the phylum level, C. sinensis infection induced Proteobacteria increased and Firmicutes reduced. At the genus level, the relative abundance of Pseudomonas and Staphylococcus increased significantly, while Enterococcus decreased prominently in infected groups (P < 0.05). The PICRUSt analysis further showed remarkably different metabolic pathways between the two groups.

Conclusion

C. sinensis infection could modify the biliary microbiota, increasing the abundance and changing the phylogenetic composition of bacterial in biliary obstruction patients. This study may help deepen the understanding of the host-biliary microbiota interplay with C. sinensis infection on the background of biliary obstruction and provide new insights into understanding the pathogenesis of clonorchiasis.

Identification of Intestinal Microbial Community in Gallstone Patients with Metagenomic Next-Generation Sequencing

Gallstone disease (GD) is one of the most common gastrointestinal diseases worldwide. Nowadays, intestinal microbiota are thought to play important roles in the formation of gallstones. In our study, human fecal samples were extracted for metagenomic next-generation sequencing (mNGS) on the Illumina HiSeq platform, followed by bioinformatics analyses. Our results showed that there was a particular intestinal micro-ecosystem in GD patients. In contrast to healthy people, the sequences of Bacteroidetes, Bacteroides and Thetaiotaomicron were obviously more abundant in GD patients at phylum, genus and species levels, respectively. On the other hand, the glycan metabolism and drug resistance, especially for the β-lactams, were the most profound functions of gut microbes in GD patients compared to those in normal subjects. Furthermore, a correlation analysis drew out that there existed a significant relationship between the serum levels of biochemical indicators and abundances of intestinal microbes in GD patients. Our results illuminate both the composition and functions of intestinal microbiota in GD patients. All in all, our study can broaden the insight into the potential mechanism of how gut microbes affect the progression of gallstones to some extent, which may provide potential targets for the prevention, diagnosis or treatment of GD.

Dietary diosgenin transcriptionally down-regulated intestinal NPC1L1 expression to prevent cholesterol gallstone formation in mice

BACKGROUND

Cholesterol gallstone disease is a common disease. Reducing cholesterol burden is important to prevent/treat gallstone. In this study, we investigated the application of diosgenin (DG) to prevent the formation of gallstone in mice.

METHODS

Adult male C57BL/6J mice were fed with the lithogenic diet (LD) only or LD supplemented with DG or ezetimibe for 8 weeks. Incidences of gallstone formation were documented. Intestine and liver tissues were collected to measure the lipid contents and expression of genes in cholesterol metabolism. Caco2 cells were treated with DG to monitor the regulation on cholesterol absorption and the transcriptional regulation of Npc1l1 gene. Changes of gut microbiota by DG was analyzed. Intraperitoneal injection of LPS on mice was performed to verify its effects on STAT3 activation and Npc1l1 expression in the small intestine.

RESULTS

LD led to 100% formation of gallstones in mice. In comparison, dietary DG or ezetimibe supplementary completely prevents gallstones formation. DG inhibited intestinal cholesterol absorption in mice as well as in Caco2 cells by down-regulation of Npc1l1 expression. DG could directly inhibit phosphorylation of STAT3 and its transcriptional regulation of Npc1l1 expression. Furthermore, DG could modulate gut microbiota profiles and LPS mediated STAT3 activation and Npc1l1 expression.

CONCLUSION

Our results demonstrated that dietary DG could inhibit intestinal cholesterol absorption through decreasing NPC1L1 expression to prevent cholesterol gallstone formation.

Causal associations between human gut microbiota and cholelithiasis: a mendelian randomization study

Background

There was some evidence that gut microbiota was closely related to cholelithiasis, but the causal relationship between them remained unclear. In this study, we try to use Two-sample Mendelian randomization (MR) to clarify the potential causal relationship between gut microbiota and cholelithiasis.

Methods

Summary Genome-Wide Association Studies (GWAS) statistical data for gut microbiota was obtained from MiBioGen, and the data of cholelithiasis was obtained from UK Biobank (UKB). Two-sample MR analyses were performed to assess causalities between gut microbiota and cholelithiasis mainly using the inverse-variance weighted (IVW) method. Sensitivity analyses were used to determine the robustness of the MR results. Reverse MR analyses were performed to examine the reverse causal association.

Results

Our research results, based primarily on the IVW method, support the existence of a causal relationship between nine gut microbial taxa and cholelithiasis. We observed a positive association between Genus Butyrivibrio (p=0.032), Genus Lachnospiraceae_UCG_001 (p=0.015), Genus Ruminococcaceae_NK4A214_group (p=0.003), Genus Ruminococcaceae_UCG_011 (p=0.010) and cholelithiasis, while Order Rhodospirillales (p=0.031), Genus Actinomyces (p=0.010), Genus Phascolarctobacterium (p=0.036), Genus Rikenellaceae_RC9_gutgroup (p=0.023), Genus Ruminococcaceae_UCG_013 (p=0.022) may be associated with a reduced risk of cholelithiasis. We did not find a reverse causal relationship between cholelithiasis and 9 specific gut microbial taxa.

Conclusions

This is the first mendelian randomization study to explore the causalities between specific gut microbiota taxa and cholelithiasis, which may provide new ideas and a theoretical basis for the prevention and treatment of cholelithiasis in the future.

Gastrointestinal microbiome and cholelithiasis: Current status and perspectives

Cholelithiasis is a common digestive disease affecting 10% to 15% of adults. It imposes significant global health and financial burdens. However, the pathogenesis of cholelithiasis involves several factors and is incompletely elucidated. In addition to genetic predisposition and hepatic hypersecretion, the pathogenesis of cholelithiasis might involve the gastrointestinal (GI) microbiome, consisting of microorganisms and their metabolites. High-throughput sequencing studies have elucidated the role of bile, gallstones, and the fecal microbiome in cholelithiasis, associating microbiota dysbiosis with gallstone formation. The GI microbiome may drive cholelithogenesis by regulating bile acid metabolism and related signaling pathways. This review examines the literature implicating the GI microbiome in cholelithiasis, specifically gallbladder stones, choledocholithiasis, and asymptomatic gallstones. We also discuss alterations of the GI microbiome and its influence on cholelithogenesis.

Gastrointestinal microbiome and cholelithiasis: Current status and perspectives

Cholelithiasis is a common digestive disease affecting 10% to 15% of adults. It imposes significant global health and financial burdens. However, the pathogenesis of cholelithiasis involves several factors and is incompletely elucidated. In addition to genetic predisposition and hepatic hypersecretion, the pathogenesis of cholelithiasis might involve the gastrointestinal (GI) microbiome, consisting of microorganisms and their metabolites. High-throughput sequencing studies have elucidated the role of bile, gallstones, and the fecal microbiome in cholelithiasis, associating microbiota dysbiosis with gallstone formation. The GI microbiome may drive cholelithogenesis by regulating bile acid metabolism and related signaling pathways. This review examines the literature implicating the GI microbiome in cholelithiasis, specifically gallbladder stones, choledocholithiasis, and asymptomatic gallstones. We also discuss alterations of the GI microbiome and its influence on cholelithogenesis.

Research progress on the immune microenvironment of the gallbladder in patients with cholesterol gallstones

Cholesterol gallstones are very common in hepatobiliary surgery and have been studied to a certain extent by doctors worldwide for decades. However, the mechanism of cholesterol gallstone formation is not fully understood, so there is currently no completely effective drug for the treatment and prevention of cholesterol gallstones. The formation and development of cholesterol gallstones are caused by a variety of genetic and environmental factors, among which genetic susceptibility, intestinal microflora disorders, impaired gallbladder motility, and immune disorders are important in the pathogenesis of cholesterol gallstones. This review focuses on recent advances in these mechanisms. We also discuss some new targets that may be effective in the treatment and prevention of cholesterol gallstones, which may be hot areas in the future.

Adipose tissue, bile acids, and gut microbiome species associated with gallstones after bariatric surgery

Several risk factors are associated with gallstone disease after bariatric surgery, but the underlying pathophysiological mechanisms of gallstone formation are unclear. We hypothesize that gallstone formation after bariatric surgery is induced by different pathways compared to gallstone formation in the general population, since postoperative formation occurs rapidly in patients who did not develop gallstones in preceding years. To identify both pathophysiological and potentially protective mechanisms against postoperative gallstone formation, we compared the preoperative fasting metabolome, fecal microbiome, and liver and adipose tissue transcriptome obtained before or during bariatric surgery of obese patients with and without postoperative gallstones. In total, 88 patients were selected from the BARIA longitudinal cohort study. Within this group, 32 patients had postoperative gallstones within two years. Gut microbiota metagenomic analyses showed group differences in abundance of 41 bacterial species, particularly abundance of Lactobacillaceae and Enterobacteriaceae in patients without gallstones. Subcutaneous adipose tissue transcriptomic analyses revealed four genes that were suppressed in gallstone patients compared to patients without gallstones. These baseline gene expression and gut microbiota composition differences might relate to protective mechanisms against gallstone formation after bariatric surgery. Moreover, baseline fasting blood samples of patients with postoperative gallstones showed increased levels of several bile acids. Overall, we revealed different genes and bacteria associated with gallstones than those previously reported in the general population, supporting the hypothesis that gallstone formation after bariatric surgery follows a different trajectory. Further research is necessary to confirm the involvement of the bile acids, adipose tissue activity, and microbial species observed here.

A systematic review on omics data (metagenomics, metatranscriptomics, and metabolomics) in the role of microbiome in gallbladder disease

Microbiotas are the range of microorganisms (mainly bacteria and fungi) colonizing multicellular, macroscopic organisms. They are crucial for several metabolic functions affecting the health of the host. However, difficulties hamper the investigation of microbiota composition in cultivating microorganisms in standard growth media. For this reason, our knowledge of microbiota can benefit from the analysis of microbial macromolecules (DNA, transcripts, proteins, or by-products) present in various samples collected from the host. Various omics technologies are used to obtain different data. Metagenomics provides a taxonomical profile of the sample. It can also be used to obtain potential functional information. At the same time, metatranscriptomics can characterize members of a microbiome responsible for specific functions and elucidate genes that drive the microbiotas relationship with its host. Thus, while microbiota refers to microorganisms living in a determined environment (taxonomy of microorganisms identified), microbiome refers to the microorganisms and their genes living in a determined environment and, of course, metagenomics focuses on the genes and collective functions of identified microorganisms. Metabolomics completes this framework by determining the metabolite fluxes and the products released into the environment. The gallbladder is a sac localized under the liver in the human body and is difficult to access for bile and tissue sampling. It concentrates the bile produced in the hepatocytes, which drains into bile canaliculi. Bile promotes fat digestion and is released from the gallbladder into the upper small intestine in response to food. Considered sterile originally, recent data indicate that bile microbiota is associated with the biliary tract’s inflammation and carcinogenesis. The sample size is relevant for omic studies of rare diseases, such as gallbladder carcinoma. Although in its infancy, the study of the biliary microbiota has begun taking advantage of several omics strategies, mainly based on metagenomics, metabolomics, and mouse models. Here, we show that omics analyses from the literature may provide a more comprehensive image of the biliary microbiota. We review studies performed in this environmental niche and focus on network-based approaches for integrative studies.

FXR Signaling-Mediated Bile Acid Metabolism Is Critical for Alleviation of Cholesterol Gallstones by Lactobacillus Strains

Cholesterol gallstone (CGS) disease is characterized by an imbalance in bile acid (BA) metabolism and is closely associated with gut microbiota disorders. However, the role and mechanism by which probiotics targeting the gut microbiota attenuate cholesterol gallstones are still unknown. In this study, Limosilactobacillus reuteri strain CGMCC 17942 and Lactiplantibacillus plantarum strain CGMCC 14407 were individually administered to lithogenic-diet (LD)-fed mice for 8 weeks. Both Lactobacillus strains significantly reduced LD-induced gallstones, hepatic steatosis, and hyperlipidemia. These strains modulated BA profiles in the serum and liver, which may be responsible for the activation of farnesoid X receptor (FXR). At the molecular level, L. reuteri and L. plantarum increased ileal fibroblast growth factor 15 (FGF15) and hepatic fibroblast growth factor receptor 4 (FGFR4) and small heterodimer partner (SHP). Subsequently, hepatic cholesterol 7α-hydroxylase (CYP7A1) and oxysterol 7α-hydroxylase (CYP7B1) were inhibited. Moreover, the two strains enhanced BA transport by increasing the levels of hepatic multidrug resistance-associated protein homologs 3 and 4 (Mrp3/4), hepatic multidrug resistance protein 2 (Mdr2), and the bile salt export pump (BSEP). In addition, both L. reuteri and L. plantarum reduced LD-associated gut microbiota dysbiosis. L. reuteri increased the relative abundance of Muribaculaceae, while L. plantarum increased that of Akkermansia. The changed gut microbiota was significantly negatively correlated with the incidence of cholesterol gallstones and the FXR-antagonistic BAs in the liver and serum and with the FXR signaling pathways. Furthermore, the protective effects of the two strains were abolished by both global and intestine-specific FXR antagonists. These findings suggest that Lactobacillus might relieve CGS through the FXR signaling pathways.

IMPORTANCE Cholesterol gallstone (CGS) disease is prevalent worldwide. None of the medical options for prevention and treatment of CGS disease are recommended, and surgical management has a high rate of recurrence. It has been reported that the factors involved in metabolic syndrome are highly connected with CGS formation. While remodeling of dysbiosis of the gut microbiome during improvement of metabolic syndrome has been well studied, less is known about prevention of CGS formation after regulating the gut microbiome. We used the lithogenic diet (LD) to induce an experimental CGS model in C57BL/6J mice to investigate protection against CGS formation by Limosilactobacillus reuteri strain CGMCC 17942 and Lactiplantibacillus plantarum strain CGMCC 14407. We found that these L. reuteri and L. plantarum strains altered the bile acid composition in mice and improved the dysbiosis of the gut microbiome. These two Lactobacillus strains prevented CGS formation by fully activating the hepatic and ileal FXR signaling pathways. They could be a promising therapeutic strategy for treating CGS or preventing its recurrence.

Gut Microbial Profile in Asymptomatic Gallstones

There are few studies on the changes of gut microbiota in patients with gallstones, especially in patients with asymptomatic gallstones, and there are some deficiencies in these studies, for instance, the effects of metabolic factors on gut microbiota are not considered. Here, we selected 30 asymptomatic gallstone patients from the survey population, and 30 controls according to the age and BMI index matching principle. The 16SrDNA technology was used to detect and compare the structural differences in the gut microbiota between the two groups. Compared with healthy controls, the abundance of gut microbiota in patients with gallstones increased significantly, while the microbiota diversity decreased. At the level of phylum, both groups were dominated by Firmicutes, Bacteroides, Proteobacteria, and Actinobacteria. At the genus level, there were 15 species with significant differences in abundance between the two groups. Further subgroup analysis found that only unclassified Lactobacillales showed differences in the intestines of gallstones patients with hypertension, non-alcoholic fatty liver disease, or patients with elevated BMI (≧24). The structure of gut microbiota in patients with gallstones changed significantly, and this might be related to the occurrence of gallstones, rather than metabolic factors such as hypertension, non-alcoholic fatty liver disease, and obesity.

Association between glucagon-like peptide-1 receptor agonists and biliary-related diseases in patients with type 2 diabetes: A nationwide cohort study

STUDY OBJECTIVE

Clinical trials have suggested that glucagon-like peptide-1 receptor agonists (GLP-1RAs) may be associated with a higher risk of biliary-related diseases in patients with type 2 diabetes. Limited real-world studies have examined the comparative biliary safety of GLP-1RAs versus other antihyperglycemic drugs. We aimed to estimate the comparative risk of biliary-related diseases between GLP-1RAs and sodium glucose cotransporter 2 inhibitors (SGLT2is), which are indicated for patients with similar diabetes severity in Taiwan.

DESIGN

Retrospective cohort study.

DATA SOURCE

Taiwan National Health Insurance Database during 2011 to 2018.

PATIENTS

Patients with type 2 diabetes who initiated GLP-1RAs or SGLT2is.

INTERVENTION

GLP-1RAs versus SGLT2is.

MEASUREMENTS AND MAIN RESULTS

We used an on-treatment approach to examine the effect of continuous use and an intention-to-treat approach to assess the effect of initiation of GLP-1RAs versus SGLT2is. We used Coxregression models to estimate the hazard ratios (HRs) and 95% confidenceintervals (CIs) for the composite hospitalized biliary-related diseases, including acute cholecystitis or cholecystectomy, choledocholithiasis, and acute cholangitis, after matching each GLP-1RA initiator to up to 10 SGLT2iinitiators using propensity scores (PSs). Among 78,253 PS-matched patients, GLP-1RA use was associated with a numerically higher risk of biliary-related diseases versus SGLT2i use in the on-treatment analysis, with an HR of 1.20 (95% CI, 0.93-1.56) for the composite outcome, an HR of 1.22 (95% CI, 0.92-1.62) for acute cholecystitis or cholecystectomy, an HR of 1.20 (95% CI, 0.69-2.07) for choledocholithiasis, and an HR of 1.14 (95% CI,0.82-2.42) for acute cholangitis. The HRs were more pronounced in theintention-to-treat analysis (1.27 [95% CI, 1.05-1.53] for the composite outcome, 1.29 [95% CI, 1.04-1.58] foracute cholecystitis or cholecystectomy, 1.74 [95% CI, 1.23-2.46] for choledocholithiasis, and 1.31 [95% CI, 0.89-1.94] for acute cholangitis). The increased risk of the composite outcome associated with GLP-1RAs was more evident in patients aged 〉60 years, women, and 120 days after treatment initiation. Liraglutide, but not dulaglutide, was associated with an elevated risk.

CONCLUSIONS

GLP-1RAs might be associated with an elevated risk of biliary-related diseases compared to SGLT2is in Asian patients with type 2 diabetes.

Gallstone Disease and Bacterial Metabolic Performance of Gut Microbiota in Middle-Aged and Older Patients

Background

Gallstone disease (GSD) is more commonly presented in aged people.

Purpose

The purpose of the study was to explore the insights of metabolic performance of bacterial species from gut microbiota as well as the clinical background in middle-aged and elderly patients with GSD.

Patients and Methods

This is an observational study concerning 120 research participants. Of those, 90 patients with symptomatic GSD addressed for cholecystectomy, average age 59.83 ± 15.32 years: 45 with cholesterol rich gallstones (CGSs), 45 with pigment gallstones (PGSs) and 30 healthy controls joined this observational study. Clinical examination, lab work-ups, upper and lower digestive video-endoscopies, abdominal ultrasound/CT and gallbladder motility assessment by Dodd’s method were performed. Overall stool dysbiosis (DB) was assessed as 1 = minor, 2 = mild, 3 = severe, species being identified by matrix-assisted laser desorption ionization method. Stool samples from dysbiotic patients were analyzed by a next generation sequencing method with operational taxonomic unit identification.

Results

Patients with GSD presented with a significant high range of overall gut DB (p < 0.0001) when compared with controls. Those with CGSs compared with those having PGSs displayed significant clinical differences related to elderly age, lifestyle and diet particularities, obesity, dyslipidemia, nonalcoholic fatty liver disease, hypertension, type 2 diabetes mellitus or impaired glucose tolerance, as well as motility disturbances of gallbladder with a decrease of the ejection fraction. Significant increase of overall DB range and alterations of several functional bacterial species with a decrease of butyrate, lactate, acetate/propionate and methane producers, mucin degrading bacteria, biodiversity index of microbiota, as well as an increase of lipopolysaccharide positive bacteria were significantly present in patients with CGSs.

Conclusion

Middle-aged and elderly patients with GSD and a clinical background characterized by particular lifestyle, metabolic and gallbladder motility issues displayed significant modifications of biodiversity, overall gut DB and alterations of several functional bacterial species, with a decrease of their metabolic performance.

Curcumin Supplementation Ameliorates Bile Cholesterol Supersaturation in Hamsters by Modulating Gut Microbiota and Cholesterol Absorption

Curcumin is a polyphenol that has been shown to have prebiotic and cholesterol-lowering properties. This study aimed to investigate the impact of curcumin on bile cholesterol supersaturation and the potential mechanistic role of intestinal microbiota and cholesterol absorption. Male hamsters (n = 8) were fed a high-fat diet (HFD) supplemented with or without curcumin for 12 weeks. Results showed that curcumin significantly decreased cholesterol levels in the serum (from 5.10 to 4.10 mmol/L) and liver (from 64.60 to 47.72 nmol/mg protein) in HFD-fed hamsters and reduced the bile cholesterol saturation index (CSI) from 1.64 to 1.08 due to the beneficial modifications in the concentration of total bile acids (BAs), phospholipids and cholesterol (p < 0.05). Gut microbiota analysis via 16S rRNA sequencing revealed that curcumin modulated gut microbiota, predominantly increasing microbiota associated with BA metabolism and short-chain fatty acid production, which subsequently up-regulated the expression of hepatic cholesterol 7-alpha hydroxylase and increased the synthesis of bile acids (p < 0.05). Furthermore, curcumin significantly down-regulated the expression of intestinal Niemann−Pick C1-like protein 1(NPC1L1) in hamsters and reduced cholesterol absorption in Caco-2 cells (p < 0.05). Our results demonstrate that dietary curcumin has the potential to prevent bile cholesterol supersaturation through modulating the gut microbiota and inhibiting intestinal cholesterol absorption.

Alterations of gut microbiome and metabolite profiles in choledocholithiasis concurrent with cholangitis

BACKGROUND AND AIMS

Gut microbiota and their metabolic products might play important roles in regulating the pathogenesis of choledocholithiasis concurrent with cholangitis (CC). The aim of this study was to explore the characteristic gut dysbiosis, metabolite profiles and the possible roles in patients with CC.

METHODS

A case-control study was carried out to analyze the alterations in the intestinal microbiota and their metabolites in patients with CC (n = 25) compared with healthy controls (HCs) (n = 25) by metagenomic sequencing to define the gut microbiota community and liquid chromatography/mass spectrometry (LC/MS) analysis to characterize the metabolite profiles.

RESULTS

Significantly reduced Shannon diversity index (p = 0.043) and differential overall fecal microbiota community in CCs were observed. Twelve dominant altered species were identified and analyzed (LDA score > 3.0, p < 0.05) (Q value < 0.05), including unclassified_f_Enterobacteriaceae, Escherichia_coli, Roseburia_faecis and Eubacterium rectale. Moreover, the levels of KEGG pathways related to biofilm formation of Escherichia coli, lipopolysaccharide (LPS) biosynthesis, and the metabolism of propanoate and glutathione in CCs were significantly altered. Finally, 47 markedly changed metabolites (VIP > 1.0 and p < 0.05), including low level of kynurenic acid (KYNA) and high concentration of N-palmitoylsphingosine involving tryptophan metabolism and sphingolipid signaling pathways, were identified to validate aberrant metabolic patterns in CCs, and multiple correlated metabolic modules involving bile inflammation were altered in CCs.

CONCLUSION

Our study provides novel insights into compositional and functional alterations in the gut microbiome and metabolite profiles in CC and the underlying mechanisms between gut microbiota and bile inflammation.

Pomegranate fruit pulp polyphenols reduce diet-induced obesity with modulation of gut microbiota in mice

BACKGROUND

Pomegranate is a rich source of polyphenols and has been used as a dietary supplement and pharmaceutical ingredient. This study aimed to investigate the pomegranate fruit pulp polyphenols (PFP) with regard to their anti-obesity activity and gut microbiota-modulating effect in mice. Thirty-six 4-week-old specific pathogen-free C57BL/6J mice (weight: 17.7-20.8 g) were randomly divided into three groups and fed with low-fat diet (10% fat energy), high-fat diet (HFD) (45% fat energy), or HFD supplemented with PFP by intragastric administration for 14 weeks. The obesity-related clinical indicators were investigated, and the composition of fecal microbiota was analyzed by 16S rRNA sequencing.

RESULTS

Our results showed that PFP treatment reduced HFD-induced body weight gain by 35.23% (P < 0.05), steatosis scores by 50% (P < 0.05) and insulin resistance by 56.84% (P < 0.05), compared with the mice fed HFD alone. Moreover, compared with the mice in the HFD group, PFP supplement changed the composition of the gut microbiota, and enriched Akkermansia muciniphila, Parabacteroides distasonis, Bacteroides acidifaciens, Mucispirillum schaedleri and Lachnospiraceae bacterium 28-4, which were negatively correlated with physical biomarkers, including body weight, glucose, triglycerides and total cholesterol.

CONCLUSION

PFP alleviated HFD-induced obesity, insulin resistance and hepatic steatosis in mice, and the changes in the gut microbiota might be one of the potential mechanisms through which PFP improved obesity and obesity-related disorders, eventually benefiting the recipient. © 2021 Society of Chemical Industry.

Dyspepsia and Gut Microbiota in Female Patients with Postcholecystectomy Syndrome

BACKGROUND

Gallstone disease (GSD) represents one of the most frequent digestive disorders, highly reported in female gender. The purpose of the study was to explore the clinical and gut microbiota particularities of female patients with postcholecystectomy syndrome (PCS) and the possible relationship between gut dysbiosis (DB) and abdominal complaints.

PATIENTS AND METHODS

In total, 129 female participants: 104 outpatients divided into two equal groups, 52 PCS (+), 52 PCS (-) and 25 healthy controls were consecutively enrolled in this observational study. Patients underwent clinical examination with assessment of pain, bloating, transit disturbances, abdominal ultrasound/computer tomography/magnetic resonance imaging/endoscopic retrograde cholangiopancreatography, upper and lower digestive endoscopies. Laboratory work-ups and stool microbiology assessments were performed for all study participants (patients and controls). Stool microorganisms were identified by matrix-assisted laser desorption ionization - time-of-flight- mass spectrometry and in patients with DB also by next-generation sequencing.

RESULTS

Older age, complicated gallstones disease, associated conditions like diabetes mellitus/impaired glucose tolerance and irritable bowel syndrome were significantly present in PCS (+) group, as well as sedentary lifestyle and diets characterized by a low fiber intake (p<0.0001). PCS (+) patients displayed significant differences related to the incidence and severity of overall gut microbiota DB, decreased H index of biodiversity and the unbalanced Firmicutes/Bacteroidetes (F/B) ratios by comparison to the PCS (-) group (p<0.0001). Strong positive correlations of the severity of overall DB with bloating and the intestinal habit disorders, as well as of F/B ratios to all abdominal symptoms were noted.

CONCLUSION

PCS in female patients was associated with older age, sedentary lifestyle, specific dietary habits, history of complicated gallstone disease, diabetes mellitus/impaired glucose tolerance and irritable bowel syndrome, as well as gut microbiota particularities. Overall DB and unbalanced F/B ratios were strongly correlated to abdominal complaints.

Adult schistosomes have an epithelial bacterial population distinct from the surrounding mammalian host blood

Background

Schistosomiasis is a neglected tropical parasitic and chronic disease affecting hundreds of millions of people. Adult schistosomes reside in the blood stream of the definitive mammalian host. These helminth parasites possess two epithelial surfaces, the tegument and the gastrodermis, both of which interact with the host during immune evasion and in nutrient uptake.

Methods

Female ARC Swiss mice (4–6 weeks old) were infected percutaneously with Schistosoma japonicum cercariae freshly shed from Oncomelania hupensis quadrasi snails (Philippines strain). Fluorescent in situ hybridisation (FISH) was performed by using fresh adult S. japonicum perfused from those infected mice. Adult S. japonicum worms were processed to isolate the tegument from the carcass containing the gastrodermis; blood and bile were collected individually from infected and uninfected mice. Total DNA extracted from all those samples were used for microbiome profiling.

Results

FISH and microbiome profiling showed the presence of bacterial populations on two epithelial surfaces of adult worms, suggesting they were distinct not only from the host blood but also from each other. Whereas microbial diversity was reduced overall in the parasite epithelial tissues when compared with that of host blood, specific bacterial taxa, including Anoxybacillus and Escherichia, were elevated on the tegument. Minimal differences were evident in the microbiome of host blood during an active infection, compared with that of control uninfected blood. However, sampling of bile from infected animals identified some differences compared with controls, including elevated levels of Limnohabitans, Clostridium and Curvibacter.

Conclusions

Using FISH and microbial profiling, we were able to demonstrate, for the first time, that bacteria are presented on the epithelial surfaces of adult schistosomes. These schistosome surface-associated bacteria, which are distinct from the host blood microenvironment, should be considered as a new and important component of the host-schistosome interaction. The importance of individual bacterial species in relation to schistosome parasitism needs further elucidation.

Pomegranate peel anthocyanins prevent diet-induced obesity and insulin resistance in association with modulation of the gut microbiota in mice

PURPOSE

Pomegranate peels are rich in anthocyanins. The present study aimed to explore the beneficial effects of pomegranate peel anthocyanins (PPA) on obesity and gut microbiota in mice with high-fat diet (HFD)-induced obesity.

METHODS

Specific pathogen-free (SPF) male C57BL/6 J mice were randomly divided into three groups and fed with low-fat diet (LFD, 10% fat energy), HFD (45% fat energy), or HFD supplemented with PPA by intragastric administration for 15 weeks. Body weight and food intake were monitored weekly. The obesity-related biochemical indexes and hepatic gene expression levels were determined. The compositions of the gut microbiota were analyzed by 16S rRNA sequencing, and the association between the gut microbiota and obesity-related indicators was investigated by Spearman correlation analysis.

RESULTS

The results showed that the body weight gain, steatosis scores and insulin resistance index in the PPA group decreased by 27.46%, 56.25%, and 46.07%, respectively, compared to the HFD group. Gene expression analysis indicated that PPA supplement improved the genes expression profiles involved in glucose and lipid metabolism compared with the mice fed HFD alone. Meanwhile, PPA significantly changed the composition of the gut microbiota, which were closely correlated with the obesity-related biomarkers.

CONCLUSION

This study suggested that PPA could be a beneficial treatment option for alleviating HFD-induced obesity and related metabolic disorders by targeting microbiota and lipid metabolism.

The effect of Tauroursodeoxycholic acid (TUDCA) and gut microbiota on murine gallbladder stone formation

INTRODUCTION AND OBJECTIVES

The incidence of gallstone-related disease steadily increased in the last few years. Here, we aimed to investigate the effect of tauroursodeoxycholic acid¹ (TUDCA) on preventing cholesterol gallstones formation in high-fat fed (HFD) mice.

MATERIAL AND METHODS

Specific pathogen-free male C57Bl/6 mice were fed a lithogenic diet² (LD group) alone or in combination with TUDCA (5g/kg diet) for 8 weeks. Upon sacrifice, serum, gallbladder, liver and small intestine were collected and the formation of gallstones or crystals in the gallbladder was analyzed. Additionally, the intestinal microbiota, and bile acid composition, serum lipids and hepatic lipids were studied.

RESULTS

Cholesterol gallstones with cholesterol crystals formed in mice of the LD-fed group (15/15, 100%). However, only cholesterol crystals were found in three mice without the presence of any gallstone in the TUDCA-treated group. Both serum and hepatic total cholesterol levels in the TUDCA group were significantly decreased compared with the LD group. Concomitantly, mRNA expression of Abcg5 and Abcg8 was significantly lower in the liver of the TUDCA group whilst mRNA transcripts for Abcb11, Acat2, and Cyp27 were significantly increased compared with the LD group. Additionally, the gallbladder cholesterol saturation index (1.06±0.15) in the TUDCA group was significantly decreased compared with the LD group. Interestingly, the ratio of Firmicutes/Bacteroides in the TUDCA group was increased 3x fold.

CONCLUSIONS

TUDCA can inhibit the absorption and synthesis of lipids in the small intestine by improving the intestinal microbiota in HFD-fed mice, thus reducing gallstone formation.

Gut microbiota promotes cholesterol gallstone formation by modulating bile acid composition and biliary cholesterol secretion

Cholesterol gallstone disease is a worldwide common disease. Cholesterol supersaturation in gallbladder bile is the prerequisite for its pathogenesis, while the mechanism is not completely understood. In this study, we find enrichment of gut microbiota (especially Desulfovibrionales) in patients with gallstone disease. Fecal transplantation of gut microbiota from gallstone patients to gallstone-resistant strain of mice can induce gallstone formation. Carrying Desulfovibrionales is associated with enhanced cecal secondary bile acids production and increase of bile acid hydrophobicity facilitating intestinal cholesterol absorption. Meanwhile, the metabolic product of Desulfovibrionales, H₂S increase and is shown to induce hepatic FXR and inhibit CYP7A1 expression. Mice carrying Desulfovibrionales present induction of hepatic expression of cholesterol transporters Abcg5/g8 to promote biliary secretion of cholesterol as well. Our study demonstrates the role of gut microbiota, Desulfovibrionales, as an environmental regulator contributing to gallstone formation through its influence on bile acid and cholesterol metabolism.

Metabolic conditions associated with alterations of the gut microbiome, such as obesity and diabetes, predispose to gallstone disease. Here the authors demonstrate that the gut microbiome, in particular the genus Desulfovibrionale, contribute to gallstone formation in mice.

RNA Sequencing Analysis of Gene Expression by Electroacupuncture in Guinea Pig Gallstone Models

BACKGROUND

Clinical studies have shown that electroacupuncture (EA) promotes gallbladder motility and alleviates gallstone. However, the mechanism underlying the effects of EA on gallstone is poorly understood. In this study, the mRNA transcriptome analysis was used to study the possible therapeutic targets of EA.

METHODS

Hartley SPF guinea pigs were employed for the gallstone models. Illumina NovaSeq 6000 platform was used for the RNA sequencing of guinea pig gallbladders in the normal group (Normal), gallstone model group (Model), and EA-treated group (EA). Differently expressed genes (DEGs) were examined separately in Model vs. Normal and EA vs. Model. DEGs reversed by EA were selected by comparing the DEGs of Model vs. Normal and EA vs. Model. Biological functions were enriched by gene ontology (GO) analysis. The protein-protein interaction (PPI) network was analyzed.

RESULTS

After 2 weeks of EA, 257 DEGs in Model vs. Normal and 1704 DEGs in EA vs. Model were identified. 94 DEGs reversed by EA were identified among these DEGs, including 28 reversed upregulated DEGs and 66 reversed downregulated DEGs. By PPI network analysis, 10 hub genes were found by Cytohubba plugin of Cytoscape. Quantitative real-time PCR (qRT-PCR) verified the changes.

CONCLUSION

We identified a few GOs and genes that might play key roles in the treatment of gallstone. This study may help understand the therapeutic mechanism of EA for gallstone.

Dietary plant sterols prevented cholesterol gallstone formation in mice

Cholesterol gallstone disease is a common global condition. This study investigated the role of plant sterols (PS) in the prevention of gallstone formation and the underlying mechanisms. Adult male mice were fed a lithogenic diet (LD) alone or supplemented with PS (LD-ps), phospholipids (LD-pl) or both PS and phospholipids (LD-ps/pl) for 8 weeks. Incidences of gallstone formation were compared among the groups. Lipids in the bile, liver and serum were analyzed. The expression of genes involved in cholesterol absorption, transport and metabolism in the liver and small intestine was determined. The incidences of gallstone formation were 100% (10/10), 20% (2/10), 100% (10/10) and 40% (4/10) in the LD, LD-ps, LD-pl and LD-ps/pl groups, respectively. Serum cholesterol and intestinal cholesterol absorption were decreased in PS-supplemented mice. The expression of genes related to cholesterol transport and metabolism in the liver was down-regulated by dietary PS. PS supplementation decreased Niemann-Pick C1-like 1 expression in the small intestine and reduced intestinal cholesterol absorption. Our results demonstrated that PS could inhibit intestinal cholesterol absorption and thus prevent cholesterol gallstone formation.

Sodium butyrate alleviates cholesterol gallstones by regulating bile acid metabolism

Cholesterol overloading and bile acid metabolic disorders play an important role in the onset of cholesterol gallstone (CGS). Short-chain fatty acids (SCFAs) can regulate bile acid metabolism by modulating the gut microbiota. However, the role and mechanism by which sodium butyrate (NaB) targets bile acids to attenuate CGS are still unknown. In this study, continuous administration of 12 mg/day for 8 weeks was decreased the incidence of gallstones induced by lithogenic diet (LD) from 100% to 25%. NaB modulated SCFAs and improved the gut microbiota. The remodeling of the gut microbiota changed the bile acid compositions and decreased cecal tauro-α-muricholic acid (T-α-MCA) and tauro-β-muricholic acid (T-β-MCA) which are effective farnesoid X receptor (FXR) antagonists. The quantitative real-time PCR examination showed that NaB significantly increased levels of ileal Fxr, fibroblast growth factor-15 (Fgf-15) and small heterodimer partner (Shp) mRNA and subsequently inhibited bile acid synthesis. In addition, NaB enhanced bile acid excretion by increasing the levels of hepatic multidrug resistance protein 2 (Mdr2) and bile salt export pump (Bsep) mRNA, and it enhanced bile acid reabsorption in the intestine by increasing the levels of ileal bile acid transporter (Ibat) mRNA. In addition, NaB reduced the absorption of cholesterol in the intestine and inhibited the excretion of cholesterol in the liver, which reduced the cholesterol concentration in serum and bile. Furthermore, the protective effects of NaB administration were abolished by FXR antagonists. Taken together, our results suggest that NaB mitigates CGS by modulating the gut microbiota to regulate the FXR-FGF-15/SHP signaling pathway.

Aqueous Extract of Lysimachia christinae Hance Prevents Cholesterol Gallstone in Mice by Affecting the Intestinal Microflora

With changes in human dietary patterns, the proportion of high-fat and high-cholesterol foods in the daily diet has increased. As a result, the incidence rate of cholelithiasis is increasing rapidly. Many studies have reported on the crucial role that the intestinal microflora plays in the progression of gallstones. Although the whole herb of Lysimachia christinae, a traditional Chinese medicine, has long been extensively used as a remedy for cholelithiasis in China, its effects on the intestinal microflora remain unknown. Hence, in this study, we investigated the ability of the aqueous extract of L. christinae (LAE) to prevent cholesterol gallstones (CGSs) in model animals by affecting the intestinal microflora. The effects of LAE on body weight, serum lipid profile, visceral organ indexes, and histomorphology were studied in male C57BL/6J mice, which were induced by a lithogenic diet. After the 8-week study, CGSs formation was greatly reduced after LAE treatment. LAE also reduced body weight gain and hyperlipidemia and restored the histomorphological changes. Moreover, the intestinal microflora exhibited significant variation. In the model group fed the lithogenic diet, the abundances of the genera unclassified Porphyromonadaceae, Lactobacillus and Alloprevotella decreased, but in contrast, Akkermansia dramatically increased compared with the control check group, which was fed a normal diet; the administration of LAE reversed these changes. These results imply that L. christinae can be considered an efficient therapy for eliminating CGSs induced by a high-fat and high-cholesterol diet, which may be achieved by influencing the intestinal microflora.

Changes and Correlations of the Intestinal Flora and Liver Metabolite Profiles in Mice With Gallstones

There is increasing appreciation for the roles of the gut-liver axis in liver and gall diseases. Specific gut microbes are associated with susceptibility to gallstone diseases, while the relationship between intestinal flora and liver metabolism in the formation of gallstones remains unclear. In this study, an experimental group of model mice was given a lithogenic diet, and a control group was given a normal diet. Both groups were fed for 8 weeks. Integrating 16S rRNA gene sequencing and non-targeted metabolomics to explore the impact of the lithogenic diet on intestinal flora and liver metabolism, Spearman correlation analysis reveals the network of relationships between the intestine and liver. Our findings showed that the gut microbiome and liver metabolome compositions of the test group were significantly changed compared with those of the normal group. Through our research, biomarkers of gallstones were identified at the phylum (5), class (5), order (5), family (7), and genus levels. We predicted the function of the differential flora. We analyzed the liver metabolism of mice with gallstones paired with their flora, and the results showed that there were 138 different metabolites between the two groups. The metabolic pathways enriched by these differential metabolites are highly consistent with the functions of the disordered flora. We focused on an analysis of the relationship between deoxycholic acid, asymmetric dimethylarginine, glucosamine, tauroursodeoxycholic acid, and the disordered flora. This provides a basis for the establishment of the intestine-liver axis in gallstone disease. This research provides a theoretical basis for the research and development of probiotics and prebiotics.

Risk of aortic dissection or aneurysm in patients with gallstone disease: a retrospective cohort study in Taiwan

OBJECTIVE

This nationwide population-based cohort study was to compare the risk of aortic dissection (AD) or aortic aneurysm (AN) between the subjects with and without gallstone disease (GD). We also compare the risk of AD/AN between the patients with GD with and without cholecystectomy.

SETTING

This nationwide population-based cohort study.

PARTICIPANTS

We extracted the hospitalisation database from the National Health Insurance Research Database of Taiwan and identified a total of 343 300 patients aged ≥20 years with GD newly diagnosed between 2000 and 2010 as the study cohort, including 191 111 with cholecystectomy and 152 189 without cholecystectomy, respectively. We randomly selected those without GD as the control cohort, by 1:1 propensity score matching with the study cohort based on age, sex, comorbidities and year of the index date for GD diagnosis.

RESULTS

The incidence of AD/AN was 6.65/10 000 person-years for the GD cohort and 6.24/10 000 person-years for the non-GD cohort (adjusted HR (aHR)=1.11, 95% CI=1.09 to 1.13), respectively (p<0.001). Furthermore, the incidence of AD/AN in the patients with GD was 9.93/10 000 person-years for the non-cholecystectomy patients (aHR=1.24, 95% CI=1.22 to 1.26) and 4.63/10 000 person-years for the cholecystectomy patients (aHR=0.97, 95% CI=0.95 to 0.99), respectively (p<0.05).

CONCLUSIONS

The GD cohort was associated with and greater risk of AD/AN than the non-GD cohort, but the risk of AD/AN in the patients with GD would decrease after cholecystectomy.

The Role of Gut Microbiota on Cholesterol Metabolism in Atherosclerosis

Hypercholesterolemia plays a causal role in the development of atherosclerosis and is one of the main risk factors for cardiovascular disease (CVD), the leading cause of death worldwide especially in developed countries. Current data show that the role of microbiota extends beyond digestion by being implicated in several metabolic and inflammatory processes linked to several diseases including CVD. Studies have reported associations between bacterial metabolites and hypercholesterolemia. However, such associations remain poorly investigated and characterized. In this review, the mechanisms of microbial derived metabolites such as primary and secondary bile acids (BAs), trimethylamine N-oxide (TMAO), and short-chain fatty acids (SCFAs) will be explored in the context of cholesterol metabolism. These metabolites play critical roles in maintaining cardiovascular health and if dysregulated can potentially contribute to CVD. They can be modulated via nutritional and pharmacological interventions such as statins, prebiotics, and probiotics. However, the mechanisms behind these interactions also remain unclear, and mechanistic insights into their impact will be provided. Therefore, the objectives of this paper are to present current knowledge on potential mechanisms whereby microbial metabolites regulate cholesterol homeostasis and to discuss the feasibility of modulating intestinal microbes and metabolites as a novel therapeutic for hypercholesterolemia.

Astragalus Polysaccharides Ameliorate Diet-Induced Gallstone Formation by Modulating Synthesis of Bile Acids and the Gut Microbiota

Cholesterol gallstone (CG) disease has relationships with several metabolic abnormalities. Astragalus polysaccharides (APS) have been shown to have multiple benefits against metabolic disorders. We attempted to uncover the effect and mechanism of action of APS on diet-induced CG formation in mice. Animals were fed a chow diet or lithogenic diet (LD) with or without APS supplementation. The effect of APS on CG formation was evaluated. The level of individual bile acids (BAs) in gallbladder bile and ileum were measured by liquid chromatography-tandem mass spectrometry. Real-time reverse transcription-quantitative polymerase chain reaction and western blotting were used to assess expression of the genes involved in BA metabolism and the enterohepatic circulation. Cecal contents were collected to characterize microbiota profiles. APS ameliorated LD-induced CG formation in mice. APS reduced the level of total cholesterol, bile acid hydrophobicity index and cholesterol saturation index in gallbladder bile. The protective effect of APS might result from reduced absorption of cholic acid in the intestine and increased hepatic BA synthesis. APS relieved the LD-induced activation of the intestinal farnesoid X receptor and decreased ileal expression of fibroblast growth factor 15. In the liver, expression of cytochrome P450 (Cyp) enzyme Cyp7a1 and Cyp7b1 was increased, whereas expression of adenosine triphosphate-binding cassette (Abc) transporters Abcg5 and Abcg8 was decreased by APS. APS improved the diversity of the gut microbiota and increased the relative abundance of the Bacteroidetes phylum. APS had demonstratable benefits against CG disease, which might be associated with enhanced BA synthesis and improved gut microbiota. Our results suggest that APS may be a potential strategy for the prevention of CG disease.

Biliary Microbiota in Choledocholithiasis and Correlation With Duodenal Microbiota

Background

The pathogenesis of choledocholithiasis is closely related to the role of bacteria. However, little is known about the predictive role of bile bacteria in clinical conditions of patients and the compositional and functional characteristics of biliary microbiota in choledocholithiasis.

Methods

To investigate the predictive value of biliary bacteria, clinical data of 488 patients with choledocholithiasis were collected. The predictive value of common bile bacteria to patients’ clinical conditions was analyzed by logistic regression. Samples of bile and corresponding duodenal juice from 10 selected patients with choledocholithiasis were obtained, and the composition and function of microbial communities were analyzed based on 16S rRNA sequencing and Tax4Fun.

Results

The clinical conditions of patients with choledocholithiasis, such as recurrence, the severity of acute cholangitis, and duration of hospital stay were closely related to different species of bile bacteria as well as antimicrobial-resistant bacteria. Employing 16S rRNA sequencing, the dominant phyla of biliary and duodenal microbiota were Proteobacteria and Firmicutes. The top three core microbiota at the genus level were Escherichia–Shigella, Fusobacterium, and Enterococcus. Escherichia coli accounted for the most abundant annotated species in both. Differences in composition between biliary and duodenal microbiota were not significant according to the alpha and beta diversities. Differential abundant features were not found in biliary microbiota indicated by A linear discriminant analysis effective size algorithm. The major pathways identified in biliary and duodenal microbiota were related to membrane transport, translation, replication and repair, carbohydrate and amino acid metabolism. However, no significant difference in those major pathways, as well as antimicrobial-resistance patterns, was observed between biliary and duodenal microbiota.

Conclusion

Our study first demonstrates the predictive contribution of biliary bacteria to the clinical conditions of patients with choledocholithiasis, and then it offers new insights into the compositional and functional features of biliary and duodenal microbiota. Similarities between biliary and duodenal microbiota support the theory of bacterial duodenal–biliary reflux in patients with choledocholithiasis. Meanwhile, when it is impracticable to obtain a bile sample, duodenal juice may be used as an alternative for bacterial culture and susceptibility tests.

Gut Microbiome in a Russian Cohort of Pre- and Post-Cholecystectomy Female Patients

The last decade saw extensive studies of the human gut microbiome and its relationship to specific diseases, including gallstone disease (GSD). The information about the gut microbiome in GSD-afflicted Russian patients is scarce, despite the increasing GSD incidence worldwide. Although the gut microbiota was described in some GSD cohorts, little is known regarding the gut microbiome before and after cholecystectomy (CCE). By using Illumina MiSeq sequencing of 16S rRNA gene amplicons, we inventoried the fecal bacteriobiome composition and structure in GSD-afflicted females, seeking to reveal associations with age, BMI and some blood biochemistry. Overall, 11 bacterial phyla were identified, containing 916 operational taxonomic units (OTUs). The fecal bacteriobiome was dominated by Firmicutes (66% relative abundance), followed by Bacteroidetes (19%), Actinobacteria (8%) and Proteobacteria (4%) phyla. Most (97%) of the OTUs were minor or rare species with ≤1% relative abundance. Prevotella and Enterocossus were linked to blood bilirubin. Some taxa had differential pre- and post-CCE abundance, despite the very short time (1–3 days) elapsed after CCE. The detailed description of the bacteriobiome in pre-CCE female patients suggests bacterial foci for further research to elucidate the gut microbiota and GSD relationship and has potentially important biological and medical implications regarding gut bacteria involvement in the increased GSD incidence rate in females.

Effect and related mechanism of Yinchenhao decoction on mice with lithogenic diet-induced cholelithiasis

The aim of the present study was to investigate the effects and the underlying mechanisms of Yinchenhao Decoction (YCHD), a traditional Chinese medicine formulation, on C57BL/6 mice with lithogenic diet (LD)-induced cholelithiasis. The condition of cholelithiasis was evaluated using a six-level criteria. Levels of alanine aminotransferase (ALT), alkaline phosphatase (ALP), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) in the serum and liver tissue were measured using enzyme colorimetry. Concentrations of TC, phospholipids (PL) and total bile acids (TBA) in the bile were measured to calculate the cholesterol saturation index. Liver histopathology was microscopically observed and mRNA expression levels of ABCG5, ABCG8, SRBI, ABCB4, ABCB11 and NPC1L1 involved in cholesterol metabolism were measured using reverse transcription-quantitative PCR. The results showed that feeding mice the LD induced cholelithiasis, along with abnormal serum biochemical indices and imbalances in biliary cholesterol homeostasis. Increased ALT and ALP levels in the serum and ALT, ALP, TC and LDL-C levels in the serum and liver indicated the existence of hepatocyte injury, which were consistent with the pathological changes. YCHD treatment ameliorated the serum and hepatic biochemical abnormalities and adjusted the biliary imbalance. In addition, elevated expression of ATP-binding cassette subfamily G member 5/8, scavenger receptor class B type I and Niemann-Pick C1 Like 1 in the liver and small intestine were observed at the onset of cholelithiasis but were reversed by YCHD. Taken together, results from the present study suggest that YCHD ameliorated LD-induced cholelithiasis mice, which may be caused by improvements in biliary cholesterol supersaturation and regulation of cholesterol metabolism.

Carrying asymptomatic gallstones is not associated with changes in intestinal microbiota composition and diversity but cholecystectomy with significant dysbiosis

Gallstone disease affects up to twenty percent of the population in western countries and is a significant contributor to morbidity and health care expenditure. Intestinal microbiota have variously been implicated as either contributing to gallstone formation or to be affected by cholecystectomy. We conducted a large-scale investigation on 404 gallstone carriers, 580 individuals post-cholecystectomy and 984 healthy controls with similar distributions of age, sex, body mass index, smoking habits, and food-frequency-score. All 1968 subjects were recruited from the population-based Study-of-Health-in-Pomerania (SHIP), which includes transabdominal gallbladder ultrasound. Fecal microbiota profiles were determined by 16S rRNA gene sequencing. No significant differences in microbiota composition were detected between gallstone carriers and controls. Individuals post-cholecystectomy exhibited reduced microbiota diversity, a decrease in the potentially beneficial genus Faecalibacterium and an increase in the opportunistic pathogen Escherichia/Shigella. The absence of an association between the gut microbiota and the presence of gallbladder stones suggests that there is no intestinal microbial risk profile increasing the likelihood of gallstone formation. Cholecystectomy, on the other hand, is associated with distinct microbiota changes that have previously been implicated in unfavorable health effects and may not only contribute to gastrointestinal infection but also to the increased colon cancer risk of cholecystectomized patients.

Alterations of gut microbiome in patients with type 2 diabetes mellitus who had undergone cholecystectomy

Patients with type 2 diabetes mellitus (T2DM) have a high risk of developing cholecystic disease. The gut microbiota has been shown to be strongly associated with cholecystectomy and T2DM pathogenesis. However, alterations of the gut microbiome in patients with T2DM who had undergone cholecystectomy remain unexplored. In this study, the gut microbiomes of 14 long-term patients with T2DM who had undergone cholecystectomy (T2DIIC group) and 21 age- and/or sex-matched subjects with new-onset (T2DI group) and long-term (T2DII group) T2DM without cholecystectomy were assessed using 16S rRNA gene sequencing of stool samples. It was found that cholecystectomy could alleviate the decrease in Pielou's evenness and the increase in the relative abundances of the Firmicutes phylum and Lachnospira genus in long-term patients with T2DM compared with T2DII subjects. Moreover, cholecystectomy also significantly increased the relative abundance of the Fusobacteria phylum, as well as that of the Fusobacterium and Bilophila genera. Interestingly, the T2DIIC and T2DI groups showed higher similarities than the T2DII group with respect to patterns of gut microbiota composition and predicted gut metagenomes. In summary, cholecystectomy could partially alleviate long-term diabetes-induced dysbiosis of the gut microbiota composition and function, but alterations in T2DM patient health warrant further study.NEW & NOTEWORTHY The gut microbiome of long-term T2DM patients who had undergone cholecystectomy and age- and/or sex-matched subjects of new-onset and long-term T2DM without cholecystectomy was assessed using 16S rRNA gene sequencing in stool samples. The findings suggest that, cholecystectomy could partially alleviate long-term diabetes-induced dysbiosis of gut microbiome composition and function.

Circadian Rhythm Disruption Influenced Hepatic Lipid Metabolism, Gut Microbiota and Promoted Cholesterol Gallstone Formation in Mice

BACKGROUND

Hepatic lipid metabolism regulates biliary composition and influences the formation of cholesterol gallstones. The genes Hmgcr and Cyp7a1, which encode key liver enzymes, are regulated by circadian rhythm-related transcription factors. We aimed to investigate the effect of circadian rhythm disruption on hepatic cholesterol and bile acid metabolism and the incidence of cholesterol stone formation.

METHODS

Adult male C57BL/6J mice were fed either a lithogenic diet (LD) only during the sleep phase (time-restricted lithogenic diet feeding, TRF) or an LD ad libitum (non-time-restricted lithogenic diet feeding, nTRF) for 4 weeks. Food consumption, body mass gain, and the incidence of gallstones were assessed. Circulating metabolic parameters, lipid accumulation in the liver, the circadian expression of hepatic clock and metabolic genes, and the gut microbiota were analyzed.

RESULTS

TRF caused a dysregulation of the circadian rhythm in the mice, characterized by significant differences in the circadian expression patterns of clock-related genes. In TRF mice, the circadian rhythms in the expression of genes involved in bile acid and cholesterol metabolism were disrupted, as was the circadian rhythm of the gut microbiota. These changes were associated with high biliary cholesterol content, which promoted gallstone formation in the TRF mice.

CONCLUSION

Disordered circadian rhythm is associated with abnormal hepatic bile acid and cholesterol metabolism in mice, which promotes gallstone formation.

Gallstone Disease, Obesity and the Firmicutes/Bacteroidetes Ratio as a Possible Biomarker of Gut Dysbiosis

Obesity is a major risk factor for developing gallstone disease (GSD). Previous studies have shown that obesity is associated with an elevated Firmicutes/Bacteroidetes ratio in the gut microbiota. These findings suggest that the development of GSD may be related to gut dysbiosis. This review presents and summarizes the recent findings of studies on the gut microbiota in patients with GSD. Most of the studies on the gut microbiota in patients with GSD have shown a significant increase in the phyla Firmicutes (Lactobacillaceae family, genera Clostridium, Ruminococcus, Veillonella, Blautia, Dorea, Anaerostipes, and Oscillospira), Actinobacteria (Bifidobacterium genus), Proteobacteria, Bacteroidetes (genera Bacteroides, Prevotella, and Fusobacterium) and a significant decrease in the phyla Bacteroidetes (family Muribaculaceae, and genera Bacteroides, Prevotella, Alistipes, Paludibacter, Barnesiella), Firmicutes (genera Faecalibacterium, Eubacterium, Lachnospira, and Roseburia), Actinobacteria (Bifidobacterium genus), and Proteobacteria (Desulfovibrio genus). The influence of GSD on microbial diversity is not clear. Some studies report that GSD reduces microbial diversity in the bile, whereas others suggest the increase in microbial diversity in the bile of patients with GSD. The phyla Proteobacteria (especially family Enterobacteriaceae) and Firmicutes (Enterococcus genus) are most commonly detected in the bile of patients with GSD. On the other hand, the composition of bile microbiota in patients with GSD shows considerable inter-individual variability. The impact of GSD on the Firmicutes/Bacteroidetes ratio is unclear and reports are contradictory. For this reason, it should be stated that the results of reviewed studies do not allow for drawing unequivocal conclusions regarding the relationship between GSD and the Firmicutes/Bacteroidetes ratio in the microbiota.

The aging mouse microbiome has obesogenic characteristics

Background

During aging, there is a physiological decline, an increase of morbidity and mortality, and a natural change in the gut microbiome. In this study, we investigated the influence of the gut microbiome on different metabolic parameters in adult and aged mice.

Methods

Fecal and blood samples from adult (n = 42, 100–300 days) and aging (n = 32, 550–750 days) mice were collected. Microbiome analysis was done using QIIME2. Mouse weight and body composition were measured using NMR, and insulin and leptin levels in the blood were measured with Mouse Adipokine Magnetic Bead Panel kit. Fecal microbiota transplantation experiments from adult and aged mice into young germ-free mice were carried out in order to examine the effect of the gut microbiome of adult and aging mice on weight, body composition, insulin, and leptin.

Results

We demonstrate that the microbiomes from adult and aged mice are distinguishable. We also report changes in metabolic parameters as we observed significantly higher weight and fat mass and low lean mass in aged compared to adult mice along with high insulin and leptin levels in the blood. The transplanted gut microbiome from aged mice transferred part of the phenotypes seen in aged mice. Fat body mass and insulin levels were higher in the mice who received feces from aged mice than mice receiving feces from adult mice. In addition, they consumed more food and had a higher respiratory quotient compared to mice receiving adult feces.

Conclusions

We conclude that aged mice have a gut microbiota with obesogenic characteristics. In addition, the gut bacterial population itself is sufficient to induce some of the manifestations of obesity.

Alterations of the Bile Microbiome in Recurrent Common Bile Duct Stone

Objective

Common bile duct stone (CBDS) recurrence is associated with bile microbial structure. This study explored the structure of bile microbiome in patients with recurrent CBDS, and its relationship with the recurrence of CBDS.

Methods

Patients with recurrent CBDS (recurrence group) and controls without CBDS (control group) requiring endoscopic retrograde cholangiopancreatography (ERCP) were prospectively included. The control group was noncholelithiasis patients, mainly including benign and malignant biliary stenosis. Bile samples were collected, and bile microbiome structure was analyzed by the 16S rRNA encoding gene (V3-V4).

Results

A total of 27 patients in the recurrence group and 19 patients in the control group were included. The diversity of bile microbiome in the recurrence group was significantly lower than that in the control group (Shannon index: 2.285 vs. 5.612, P = 0.001). In terms of bile microbial distribution, patients with recurrent CBDS had significantly higher Proteobacteria (86.72% vs. 64.92%, P = 0.037), while Bacteroidetes (3.16% vs. 8.53%, P = 0.001) and Actinobacteria (0.29% vs. 6.74%, P = 0.001) are significantly lower compared with the control group at the phylum level. At the genus level, the recurrence group was mainly the Escherichia, and there was a variety of more evenly distributed microbiome in the control group, with significant differences between the two groups.

Conclusion

The diversity of bile microbiome in patients with recurrent CBDS is lower. Patients with recurrent CBDS may have bile microbial imbalance, which may be related to the repeated formation of CBDS.

Transcriptomic profiles reveal differences in zinc metabolism, inflammation, and tight junction proteins in duodenum from cholesterol gallstone subjects

Cholesterol Gallstone Disease (GSD) is a common multifactorial disorder characterized by crystallization and aggregation of biliary cholesterol in the gallbladder. The global prevalence of GSD is ~10–20% in the adult population but rises to 28% in Chile (17% among men and 30% among women). The small intestine may play a role in GSD pathogenesis, but the molecular mechanisms have not been clarified. Our aim was to identify the role of the small intestine in GSD pathogenesis. Duodenal biopsy samples were obtained from patients with GSD and healthy volunteers. GSD status was defined by abdominal ultrasonography. We performed a transcriptome study in a discovery cohort using Illumina HiSeq. 2500, and qPCR, immunohistochemistry and immunofluorescence were used to validate differentially expressed genes among additional case-control cohorts. 548 differentially expressed genes between GSD and control subjects were identified. Enriched biological processes related to cellular response to zinc, and immune and antimicrobial responses were observed in GSD patients. We validated lower transcript levels of metallothionein, NPC1L1 and tight junction genes and higher transcript levels of genes involved in immune and antimicrobial pathways in GSD patients. Interestingly, serum zinc and phytosterol to cholesterol precursor ratios were lower in GSD patients. A significant association was observed between serum zinc and phytosterol levels. Our results support a model where proximal small intestine plays a key role in GSD pathogenesis. Zinc supplementation, modulation of proximal microbiota and/or intestinal barrier may be novel targets for strategies to prevent GSD.

Pathophysiological connections between gallstone disease, insulin resistance, and obesity

Obesity and cholesterol gallstone disease (GSD) are frequently coexisting diseases; therefore and considering the current worldwide obesity epidemics, a precise understanding of the pathophysiological relationships between GSD and insulin resistance (IR) is important. Classically, obesity has been understood as a risk factor for GSD and the gallbladder (GB) viewed as a simple bile reservoir, with no metabolic roles whatsoever. However, consistent evidence has showed that both GSD and cholecystectomy associates with fatty liver and IR, raising the possibility that the GB is indeed an organ with metabolic regulatory roles. Herein, we review the pathophysiological mechanisms by which GSD, IR, and obesity are interconnected, with emphasis in the actions of the GB as a regulator of bile acids kinetics and a hormone secreting organ, with metabolic actions at the systemic level. We also examine the relationships between increased hepatic lipogenic in IR states and GSD pathogenesis. We propose a model in which GSD and hepatic IR mutually interact to determine a state of dysregulated lipid and energy metabolism that potentiate the metabolic dysregulation of obesity.

Intestinal flora imbalance affects bile acid metabolism and is associated with gallstone formation

BACKGROUND

The gut microbiota participates in the metabolism of substances and energy, promotes the development and maturation of the immune system, forms the mucosal barrier, and protects the host from pathogen attacks. Although the pathogenesis of cholesterol gallstones is still not clear, studies have suggested that gut microbiota dysbiosis plays an important role in their formation.

METHODS

Microbial DNA from faeces of normal control patients and those of patients with calculi was subjected to 16S rRNA gene sequencing to detect gene expression changes in intestinal microbes. ELISA kits were used to measure free bile acids, secondary bile acids and coprostanol according to the manufacturer's instructions. The relationship between flora and their metabolites was then analysed.

RESULTS

In the gallstone group, the diversity of intestinal bacteria and the abundances of certain phylogroups were significantly decreased (p < 0.05), especially Firmicutes (p < 0.05), the largest phylum represented by the gut microbiota. This study found an increase in free bile acids (p < 0.001) and secondary bile acids (p < 0.01) in the enterohepatic circulation. Bile salt hydrolase activity was not related to the abundances of BSH-active bacteria. 7a-dehydroxylating gut bacteria were significantly increased (p < 0.01), whereas cholesterol-lowering bacteria were significantly reduced (p < 0.05). The Ruminococcus gnavus group could be used as a biomarker to distinguish the gallstone group from the control group.

CONCLUSION

We conclude that intestinal flora imbalance affects bile acid and cholesterol metabolism and is associated with gallstone formation.

Proteobacteria Acts as a Pathogenic Risk-Factor for Chronic Abdominal Pain and Diarrhea in Post-Cholecystectomy Syndrome Patients: A Gut Microbiome Metabolomics Study

Background

Laparoscopic cholecystectomy (LC) is regarded as the criterion standard for gallstone therapy, but post-cholecystectomy syndrome (PCS) is a common complication. This study aimed to analyze and identify differences in gut microbiome in PCS patients.

Material/Methods

This study involved 8 PCS patients (RS1), 8 asymptomatic PCS patients (RS2), and 8 healthy individuals (RS3). Genomic DNA of gut microbiome was extracted and amplified with CTAB method. PCR products were sequenced with Illumina High-Through Sequencing. Sequencing data were analyzed with QIIME software. Effective sequence of bacterial 16S-rRNA gene was clustered into OTUs using UPARSE software. Species annotations were evaluated using Mothur software. QIIME software was used to conduct complexity analysis and calculate UniFrac distances. R software was used to generate PCoA plots.

Results

Bacterial 16S-rDNA gene sequences showed that the effective species annotative data were more than 97%. According to Ternary plot, Firmicutes and Bacteroidetes had similar abundance and contents among the 3 groups. Contents of Proteobacteria in RS1 were higher compared to RS2 and RS3. Bacterial genomic DNAs samples were clustered together in the same group; however, distances were relative far between different groups. RS1 illustrated significantly higher abundance of Proteobacteria colonies compared to healthy people (p<0.05), and illustrated higher abundance of Verrucomicrobia and lower abundance of Bacteroidetes and Firmicutes, but without significant differences (p>0.05).

Conclusions

Gut microbiome of PCS patients was dominated by Proteobacteria in feces and contained little Firmicutes and Bacteroidetes. The enhanced abundance of Proteobacteria might be the highly pathogenic risk factor for chronic abdominal pain and diarrhea in PCS patients.

The relationship between the structural characteristics of lactobacilli-EPS and its ability to induce apoptosis in colon cancer cells in vitro

Colon cancer is one of the most common cancer around the world. Exopolysaccharides (EPSs) produced by lactobacilli as potential prebiotics have been found to have an anti-tumor effect. In this study, lyophilized EPSs of four Lactobacillus spp. for their impact on apoptosis in colon cancer cells (HT-29) was evaluated using flow cytometry. The relationship between capability of a lactobacilli-EPS to induce apoptosis and their monosaccharide composition, molecular weight (MW), and linkage type was investigated by HPLC, SEC, and NMR, respectively. Changes in apoptotic-markers were examined by qPCR and Western Blotting. EPSs were capable of inhibiting proliferation in a time-dependent manner and induced apoptosis via increasing the expression of Bax, Caspase 3 and 9 while decreasing Bcl-2 and Survivin. All EPSs contained mannose, glucose, and N-acetylglucosamine with different relative proportions. Some contained arabinose or fructose. MW ranged from 102-104Da with two or three fractions. EPS of L. delbrueckii ssp. bulgaricus B3 having the highest amount of mannose and the lowest amount of glucose, showed the highest apoptosis induction. In conclusion, lactobacilli-EPSs inhibit cell proliferation in HT-29 via apoptosis. Results suggest that a relationship exists between the ability of EPS to induce apoptosis and its mannose and glucose composition.