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.

Important risk factors for gallstones after laparoscopic gastrectomy: a retrospective study

Background The frequency of gallstones is higher in patients who have undergone gastrectomy than in the general population. While there have been some studies of gallstone formation after open gastrectomy, there are few reports of gallstones after laparoscopic gastrectomy (LG). Therefore, this study aimed to evaluate the incidence of gallstones after LG. Methods We retrospectively reviewed the records of 184 patients who underwent LG between January 2011 and May 2016 at Saiseikai Utsunomiya Hospital. After gastrectomy, abdominal ultrasonography was generally performed every 6 months for 5 years. Patients who underwent cholecystectomy before LG, underwent simultaneous cholecystectomy, and did not undergo abdominal ultrasonography, with an observation period of < 24 months, were excluded from the study. Finally, 90 patients were analyzed. Laparoscopic cholecystectomy was performed whenever biliary complications occurred. Patient characteristics were compared using the two-tailed Fisher’s exact test or Chi-square test. In addition, the risk factors for postoperative gallstones were analyzed using logistic regression analysis. Results Among the 90 patients included in this study, 60 were men (78%), and the mean age was 65.5 years. Laparoscopic total gastrectomy was performed for 15 patients and laparoscopic distal gastrectomy for 75 patients. D2 lymph node dissection was performed for 8 patients (9%), whereas 68 patients underwent LG with Roux-en-Y reconstruction (76%). Gallstones were detected after LG in 27 of the 90 (30%) patients. Multivariate analysis identified Roux-en-Y reconstruction and male sex as significant risk factors of gallstones after gastrectomy. The incidence of gallstones was significantly higher (53%) in male patients who underwent Roux-en-Y reconstruction. Symptomatic gallstones after laparoscopic cholecystectomy were found in 6 cases (6/27, 22%), and all patients underwent laparoscopic cholecystectomy. Conclusion Roux-en-Y reconstruction and male sex were identified as significant risk factors for gallstones after LG.

Prevalence of undiagnosed hypothyroidism in patients with gall bladder stones in Belagavi

Background: Contribution of hypothyroidism to gallstone formation is debated over years. With this background, the study intended to analyze the prevalence of undiagnosed hypothyroidism in patients with cholelithiasis. The aim is to understand the prevalence of hypothyroidism in patients with gallstones.Methods: A prospective, hospital-based study was done on 100 patients admitted for the management of gall stone disease in Belagavi. After initial screening, a detailed history was obtained with special reference to symptomatology and the risk factors as per proforma from patients meeting selection criteria. Thyroid function test was done on all eligible patients. Patients were divided into three groups of Euthyroid, Subclinical hypothyroid and clinical hypothyroidism. Statistical analysis used. Percentage of gall stones in different age groups and gender of the study population was calculated followed by prevalence of hypothyroidism and subclinical hypothyroidism in all the patients included.Results: Among the study population, 40% were male and 60% were female. 23 of them have subclinical hypothyroidism and 6 of them were diagnosed with hypothyroidism. Majority of subclinical hypothyroid patients (39.13%) were aged 41-60 years. Hypothyroid symptoms were shown by the study population with unknown thyroid status.Conclusions: The prevalence of hypothyroidism in cholelithiasis is 29% in the study and is significant. The study demands further studies to consider hypothyroidism as a cause /risk factor for biliary calculus.

O-B01 Role of Ursodeoxycholic acid in prevention of gallstones formation in bariatric patients: need to amend recent BOMSS guidelines

Background During rapid weight-loss phase following bariatric procedures, biliary cholesterol homeostasis is altered leading to increased propensity to gallstone formation. Incidence of gallstone formation following bariatric procedures is shown to be 10-38%. There is no consensus regarding its prevention and current BOMSS guidelines do not address this issue. This meta-analysis aims to pool high level evidence (RCTs) to assess efficacy of Ursodeoxycholic acid (UDCA) in reducing risk of gallstone formation in this cohort of patients and the need for revision of current guidelines. Methods A systematic literature search was performed using electronic databases (Medline, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, PROSPERO and Google Scholar) in line with PRISMA guidelines. Only randomised controlled trials were included without restrictions on study language, year, status of publication and patient’s age. Meta-analysis was performed using Review Manager Software to calculate pooled risk ratios (RR) using random-effects model. Results Fifteen trials were included (3952 patients analysed, 2487 in UDCA and 1465 in placebo group). The overall rate of gallstone formation was 16.0% (6.4% in UDCA vs 31.4% in placebo group). Trials included various bariatric procedures (SG/RYGB/OAGB/AGB/Gastroplasty). UDCA dose ranged from 300 to 1200mg per day. UDCA significantly reduced the risk of post-operative gallstone formation (3952 patients, RR 0.24, 95% CI 0.16-0.37, p &lt; 0.0001). The absolute risk reduction and number needed to treat (NNT) were 25% and 4 respectively. Conclusions Oral Ursodeoxycholic acid treatment following restrictive bariatric surgical procedures significantly reduces the risks of gallstone formation. As such, its regular use in first 6 months (rapid weight-loss phase) can significantly reduce the risk of complications associated with gallstones. Such treatment would be cost effective and benefit 1 in 4 patients. There is significant evidence available on benefits of using UDCA in post-operative bariatric patients and that this should be added to the recent BOMSS guidelines.

Current management of choledocholithiasis after bariatric surgery

The increasing prevalence of obesity all over world has led to a growing number of metabolic and bariatric surgeries. Bariatric surgery is more effective for weight loss than medical therapy, with Roux-en-Y gastric bypass (RYGB) being considered the gold standard of care over the past decade. Bariatric surgery and the subsequent weight loss are associated with an increased risk for the development of gallstone formation. Common bile duct stones prevalence around 10% among patients with symptomatic gallbladder stones. Choledocholithiasis can be technically challenging problem to treat in patients post-laparoscopic RYGB (LRYGB) or a biliopancreatic diversion (BPD/DS) due to the altered upper gastrointestinal anatomy. This review describes the different treatment options of common bile duct stones after malabsorptive bariatric surgery, success rate, and adverse effects of each treatment modality including enteroscopy-assisted endoscopic retrograde cholangiopancreatography (EA-ERCP), percutaneous transhepatic cholangiography (PTC), endoscopic ultrasound-directed transgastric retrograde cholangiopancreatography (EDGE), and laparoscopic-assisted ERCP (LAERCP).

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

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

Gallstone Formation Follows a Different Trajectory in Bariatric Patients Compared to Nonbariatric Patients

Since obese patients form cholesterol gallstones very rapidly after bariatric surgery, in patients who did not form gallstones during preceding years, we hypothesized that gallstone formation follows a different trajectory in bariatric patients compared to nonbariatric patients. We therefore analyzed the lipid composition of gallbladder bile derived from 18 bariatric gallstone patients and 17 nonbariatric gallstone patients (median (IQR) age, 46.0 (28.0–54.0) years; 33 (94%) female) during laparoscopic cholecystectomy using an enzymatic and lipidomics approach. We observed a higher concentration of total lipids (9.9 vs. 5.8 g/dL), bile acids (157.7 vs. 81.5 mM), cholesterol (10.6 vs. 5.4 mM), and phospholipids (30.4 vs. 21.8 mM) in bariatric gallstone patients compared to nonbariatric gallstone patients. The cholesterol saturation index did not significantly differ between the two groups. Lipidomics analysis revealed an interesting pattern. Enhanced amounts of a number of lipid species were found in the gallbladder bile of nonbariatric gallstone patients. Most striking was a fivefold higher amount of triglyceride. A concomitant ninefold increase of apolipoprotein B was found, suggesting secretion of triglyceride-rich lipoproteins (TRLs) at the canalicular pole of the hepatocyte in livers from nonbariatric gallstone patients. These findings suggest that gallstone formation follows a different trajectory in bariatric patients compared to nonbariatric patients. Impaired gallbladder emptying might explain the rapid gallstone formation after bariatric surgery, while biliary TRL secretion might contribute to gallstone formation in nonbariatric patients.

Single Cell RNA-Sequencing Reveals a Murine Gallbladder Cell Transcriptome Atlas During the Process of Cholesterol Gallstone Formation

Gallstone disease is a worldwide common disease. However, the knowledge concerning the gallbladder in the pathogenesis of cholesterol gallstone formation remains limited. In this study, using single-cell RNA sequencing (scRNA-seq) to obtain the transcriptome of gallbladder cells, we showed cellular heterogeneity and transcriptomic dynamics in murine gallbladder cells during the process of lithogenesis. Our results indicated gallbladder walls were subjected to remodeling during the process of lithogenesis. The major molecular events that happened included proliferation of epithelial cells, infiltration of immune-cells, activation of angiogenesis, and extracellular matrix modulation. Furthermore, we observed partial reversal of gallbladder cell transcriptomes by ursodeoxycholic acid treatment. This work thus provides novel and integral knowledges on the cellular changes during lithogenesis, which is of great significance to the understanding of pathogenesis and treatment of cholesterol gallstone.

Crohn’s disease of the gallbladder

Crohn’s disease (CD) is a chronic inflammatory condition, which typically involves the small and large bowel but can affect any part of the gastrointestinal tract. Common symptoms include abdominal pain, diarrhoea, fatigue, weight loss and malnutrition. Complications of CD include gallstone formation and cholecystitis. Impaired reabsorption of bile salts in the small bowel and CD-related surgeries are key factors in the development of CD-related gallstones, although other factors are also important. Direct CD-related inflammation of the gallbladder is very unusual and the typical histological features of CD are rarely encountered in cholecystectomy specimens of individuals with CD. We present a case of a man in his early 60s with CD, previous right hemicolectomy and a history of gallstones, who presented with chronic cholecystitis. Following cholecystectomy, pathological examination of the gallbladder unexpectedly demonstrated typical features of CD, including lymphoid aggregates and non-caseating mucosal granulomata.

1163 Genome-wide Association Study Reveals 55 Loci Associated with Gallstone Disease

Aim Gallstones have a prevalence of 20-40% in European populations and cause significant morbidity. Gallstones form from cholesterol and calcium bilirubinate and knowledge of genetic determinants remains incomplete. A genome-wide association study (GWAS) was performed to identify determinants of gallstones. Method A GWAS of 16,356,211 single nucleotide polymorphisms (SNPs) for 28,627 cases and 348,373 controls of European ancestry in the UK Biobank was undertaken. A logistic regression with additive allelic dosage was performed (significance: P &lt; 5*10-8). Functional annotation and linkage disequilibrium clumping were performed to reveal distinct loci. Lead SNPs were investigated by linear regression for association with plasma lipids, liver enzymes and blood count markers. Results 55 lithogenic loci were identified of which 27 are novel. Functional annotation revealed genes involved in metabolism of cholesterol, glucose, bile acids and bilirubin with corresponding changes in serum biomarkers caused by those lithogenic alleles. Several novel variants did not alter cholesterol or other biomarkers. Lithogenic variants within genes controlling intra- and paracellular transport may govern biliary composition (PCDHB4, NUP153, CLDN7) and promote lithogenic bile. Variants within genes which may influence gallbladder motility (ANO1, TMEM147) and cholangiocyte ciliogenesis (TBC1D32, ADAMTS20, DYNC2LI1, HNF1B) may promote gallstone formation through reduced biliary flow. Conclusions We identified 27 novel associations with gallstones. Impact of lithogenic alleles on serum biomarkers was highly variable demonstrating that gallstone formation is partially driven by pathways which do not influence cholesterol, glucose or bilirubin metabolism. Variants within genes that may influence biliary composition, bile flow and gallbladder motility represent new targets for research into gallstones.