Cholelithiasis, Gut Microbiota and Bile Acids after Bariatric Surgery-Can Cholelithiasis Be Prevented by Modulating the Microbiota? A Literature Review.

BACKGROUND: Cholelithiasis is one of the more common complications following bariatric surgery. This may be related to the rapid weight loss during this period, although the exact mechanism of gallstone formation after bariatric surgery has not been fully elucidated. METHODS: The present literature review focuses on risk factors, prevention options and the impact of the gut microbiota on the development of gallbladder stones after bariatric surgery. RESULTS: A potential risk factor for the development of cholelithiasis after bariatric surgery may be changes in the composition of the intestinal microbiota and bile acids. One of the bile acids-ursodeoxycholic acid-is considered to reduce the concentration of mucin proteins and thus contribute to reducing the formation of cholesterol crystals in patients with cholelithiasis. Additionally, it reduces the risk of both asymptomatic and symptomatic gallstones after bariatric surgery. Patients who developed gallstones after bariatric surgery had a higher abundance of Ruminococcus gnavus and those who did not develop cholelithiasis had a higher abundance of Lactobacillaceae and Enterobacteriaceae. CONCLUSION: The exact mechanism of gallstone formation after bariatric surgery has not yet been clarified. Research suggests that the intestinal microbiota and bile acids may have an important role in this.

Inhibition of PCSK9 prevents and alleviates cholesterol gallstones through PPARα-mediated CYP7A1 activation.

BACKGROUND & AIMS: Dysregulated cholesterol metabolism is the major factor responsible for cholesterol gallstones (CGS). Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a critical role in cholesterol homeostasis and its inhibitors secure approval for treating various cholesterol metabolic disorders such as hypercholesterolemia and cardiovascular diseases, but its role in CGS remains unclear. Our study aims to clarify mechanisms by which PCSK9 promotes CGS formation and explore the application of the PCSK9 inhibitor, alirocumab, in preventing and treating CGS. APPROACH & RESULTS: The expressions of PCSK9 were notably increased in CGS patients' serum, bile, and liver tissues compared to those without gallstones. Moreover, among CGS patients, hepatic PCSK9 was positively correlated with hepatic cholesterol and negatively correlated with hepatic bile acids (BAs), suggesting PCSK9 was involved in disrupted hepatic cholesterol metabolism related to CGS. Mechanistically, in vitro experiments demonstrated that inhibition of PCSK9 enhanced nuclear expression of PPARα by diminishing its lysosomal degradation and subsequently activated CYP7A1 transcription. Finally, inhibition of PCSK9 prevented CGS formation and dissolved the existing stones in CGS mice by elevating the conversion of cholesterol into BAs through PPARα-mediated CYP7A1 activation. Additionally, serum PCSK9 level may function as a prognostic signature to evaluate the therapeutic efficacy of PCSK9 inhibitors. CONCLUSIONS: Inhibition of PCSK9 exerts preventive and therapeutic effects on CGS by activating PPARα-mediated CYP7A1 expression and facilitating the conversion of cholesterol into BAs, which highlights the potential of PCSK9 inhibition as a promising candidate for preventing and treating CGS in clinical applications. IMPACT AND IMPLICATIONS: PCSK9 plays a pivotal role in cholesterol metabolism and its inhibitors are approved for clinical use in cardiovascular diseases. Our study observes inhibition of PCSK9 prevents and dissolves CGS by activating PPARα-mediated CYP7A1 expression and facilitating the conversion of cholesterol into BAs. Mechanistically, PCSK9 inhibition enhanced the nuclear expression of PPARα by diminishing its lysosomal degradation and subsequently activated CYP7A1 transcription. Our study sheds light on the new function and mechanism of PCSK9 in CGS, providing a novel preventive and therapeutic target with potential clinical applications.

Role of Ursodeoxycholic Acid in the Prevention of Gallstones Formation in Bariatric Patients-a Systematic Review and Meta-Analysis of Randomised Trials.

The aim of this meta-analysis was to assess whether treatment with ursodeoxycholic acid (UDCA) in patients who have undergone bariatric surgery reduces gallstone formation. A systematic literature search was performed using electronic databases (MEDLINE, Embase, CENTRAL, Web of Science, PROSPERO, Google Scholar and the WHO International Clinical Trials Registry platform). RCTs without restrictions on study language, year, status of publication and patient's age were used. Pooled risk ratios were calculated using a random-effects model. Subgroup analyses for drug dose, duration and procedure types were performed. Sensitivity analyses and a summary of findings table were generated to assess the robustness and the level of evidence provided, respectively. Fourteen trials were included (3619 patients, 2292 in UDCA vs 1327 in control group). Procedures included SG, RYGB, OAGB, AGB and Gastroplasty. UDCA dose ranged from 300 to 1200 mg per day. Gallstone formation occurred in 19.3% (8.3% in UDCA vs 38.1% in the control group). UDCA significantly reduced the risk of gallstone formation (14 trials, 3619 patients; RR 0.27, 95% CI 0.18-0.41; P < 0.001). UDCA significantly reduced the risk of symptomatic gallstone disease (6 trials, 2458 patients; RR 0.30, 95% CI 0.21-0.43; P < 0.001). No subgroup difference was found for different doses, duration and type of procedure performed. Oral UDCA treatment significantly reduces the risks of developing gallstones in postoperative bariatric patients from 38 to 8%. The use of 500 to 600 mg UDCA for 6 months is effective and should be implemented in all patients post-bariatric surgery.

Hyodeoxycholic acid attenuates cholesterol gallstone formation via modulation of bile acid metabolism and gut microbiota.

BACKGROUND & AIMS: Hyodeoxycholic acid (HDCA), a hydrophilic bile acid (BA), may prevent and suppress the formation of cholesterol gallstones (CGs). However, the mechanism by which HDCA prevents CGs formation remains unclear. This study aimed to investigate the underlying mechanism of HDCA in preventing CG formation. METHODS: C57BL/6J mice were fed either a lithogenic diet (LD), a chow diet, or LD combined with HDCA. The concentration of BAs in the liver and ileum were determined using liquid chromatography-mass spectrometry (LC-MS/MS). Genes involved in cholesterol and BAs metabolism were detected using polymerase chain reaction (PCR). The gut microbiota in the faeces was determined using 16S rRNA. RESULTS: HDCA supplementation effectively prevented LD-induced CG formation. HDCA increased the gene expression of BA synthesis enzymes, including Cyp7a1, Cyp7b1, and Cyp8b1, and decreased the expression of the cholesterol transporter Abcg5/g8 gene in the liver. HDCA inhibited LD-induced Nuclear farnesoid X receptor (Fxr) activation and reduced the gene expression of Fgf15 and Shp in the ileum. These data indicate that HDCA could prevent CGs formation partly by promoting BA synthesis in the liver and reduced the cholesterol efflux. In addition, HDCA administration reversed the LD-induced decrease in the abundance of norank_f_Muribaculaceae, which was inversely proportional to cholesterol levels. CONCLUSIONS: HDCA attenuated CG formation by modulating BA synthesis and gut microbiota. This study provides new insights into the mechanism by which HDCA prevents CG formation. LAY SUMMARY: In this study, we found that HDCA supplementation suppressed LD-induced CGs in mice by inhibiting Fxr in the ileum, enhancing BA synthesis, and increasing the abundance of norank_f_Muribaculaceae in the gut microbiota. HDCA can also downregulate the level of total cholesterol in the serum, liver, and bile.

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.

Ursodeoxycholic acid for prevention of gallstone disease after laparoscopic sleeve gastrectomy: an Atlantic Canada perspective.

BACKGROUND: Prophylactic ursodeoxycholic acid (UDCA) may be beneficial in reducing gallstone disease after bariatric surgery. The American Society for Metabolic and Bariatric Surgery (ASMBS) 2019 guidelines recommend a 6-month course of UDCA for patients undergoing laparoscopic sleeve gastrectomy (LSG). This has not been adopted broadly. This study intends to assess the effect of routine UDCA administration following LSG on symptomatic gallstone disease. METHODS: We performed a retrospective chart review of patients who underwent LSG, between 2009 and 2019, at two tertiary care centers in Atlantic Canada. At one center, UDCA 250 mg oral twice daily was routinely prescribed following LSG for 6 months to patients with an intact gallbladder. At the other center, UDCA was not prescribed. Primary and secondary outcomes were cholecystectomy and endoscopic retrograde cholangiopancreatography (ERCP) rates. Compliance with and side effects of UDCA therapy were analyzed. RESULTS: A total of 751 patients were included in the study. Patients who had prior cholecystectomy or were lost to follow up were excluded. After exclusion criteria were applied, 461 patients were included for analysis: 303 in the UDCA group and 158 in the group who did not receive UDCA. Cholecystectomy rate was not significantly associated with UDCA administration, however there was a trend towards less cholecystectomy in patients who received UDCA (8.3% vs. 13.9%, p = 0.056). ERCP rate was significantly lower in patients who received UDCA (0.3% vs 2.5%, p = 0.031). Rate of gallstone disease requiring intervention, either cholecystectomy or ERCP, was significantly decreased in patients who received UDCA (8.9% vs 15.8%, p = 0.022). The most common barriers to compliance with UDCA were cost (45.4%) and nausea (18.1%). CONCLUSION: This is the first study to demonstrate lower rates of ERCP in patients receiving routine UDCA following LSG. Our findings support the ASMBS 2019 guidelines for administering UDCA after LSG for preventing gallstone disease.

Adeno-associated virus-based caveolin-1 delivery via different routes for the prevention of cholesterol gallstone formation.

BACKGROUND: Hepatic caveolin-1 (CAV1) is reduced in cholesterol gallstone disease (CGD). Mice with CAV1 deficiency were prone to develop CGD. However, it remains unknown whether restored hepatic CAV1 expression prevents the development of CGD. METHODS: C57BL/6 mice were injected with adeno-associated virus 2/8 (AAV2/8) vectors carrying the CAV1 gene (AAV2/8CAV1) via intravenous (i.v.) or intraperitoneal (i.p.) route and then subjected to a lithogenic diet (LD) for 8 weeks. Uninjected mice were used as controls. The functional consequences of rescuing CAV1 expression by either i.v. or i.p. AAV2/8CAV1 treatment for CGD prevention and its subsequent molecular mechanisms were examined. RESULTS: CAV1 expression was reduced in the liver and gallbladder of LD-fed CGD mice. We discovered that AAV2/8CAV1 i.p. delivery results in higher transduction efficiency in the gallbladder than tail vein administration. Although either i.v. or i.p. injection of AAV2/8CAV1 improved liver lipid metabolic abnormalities in CGD mice but did not affect LD feeding-induced bile cholesterol supersaturation. In comparison with i.v. administration route, i.p. administration of AAV2/8CAV1 obviously increased CAV1 protein levels in the gallbladder of LD-fed mice, and i.p. delivery of AAV2/8CAV1 partially improved gallbladder cholecystokinin receptor (CCKAR) responsiveness and impeded bile cholesterol nucleation via the activation of adenosine monophosphate-activated protein kinase (AMPK) signaling, which induced a reduction in gallbladder mucin-1 (MUC1) and MUC5ac expression and gallbladder cholesterol accumulation. CONCLUSION: CGD prevention by i.p. AAV2/8CAV1 injection in LD-fed mice was associated with the improvement of gallbladder stasis, which again supported the notion that supersaturated bile is required but not sufficient for the formation of cholesterol gallstones. Additionally, AAV treatment via the local i.p. injection offers particular advantages over the systemic i.v. route for much more effective gallbladder gene delivery, which will be an excellent tool for conducting preclinical functional studies on the maintenance of normal gallbladder function to prevent CGD.

Cost-effectiveness of ursodeoxycholic acid in preventing new-onset symptomatic gallstone disease after Roux-en-Y gastric bypass surgery.

BACKGROUND: The aim was to evaluate the cost-effectiveness and cost-utility of ursodeoxycholic acid (UDCA) prophylaxis for the prevention of symptomatic gallstone disease after Roux-en-Y gastric bypass (RYGB) in patients without gallstones before surgery. METHODS: Data from a multicentre, double-blind, randomized placebo-controlled superiority trial were used. Patients scheduled for laparoscopic RYGB or sleeve gastrectomy were randomized to receive 900 mg UDCA or placebo for 6 months. Indicated by the clinical report, prophylactic prescription of UDCA was evaluated economically against placebo from a healthcare and societal perspective for the subgroup of patients without gallstones before surgery who underwent RYGB. Volumes and costs of in-hospital care, out-of-hospital care, out-of-pocket expenses, and productivity loss were assessed. Main outcomes were the costs per patient free from symptomatic gallstone disease and the costs per quality-adjusted life-year (QALY). RESULTS: Patients receiving UDCA prophylaxis were more likely to remain free from symptomatic gallstone disease (relative risk 1.06, 95 per cent c.i. 1.02 to 1.11; P = 0.002) compared with patients in the placebo group. The gain in QALYs, corrected for a baseline difference in health utility, was 0.047 (95 per cent bias-corrected and accelerated (Bca) c.i. 0.007 to 0.088) higher (P = 0.022). Differences in costs were -€356 (95 per cent Bca c.i. €-1573 to 761) from a healthcare perspective and -€1392 (-3807 to 917) from a societal perspective including out-of-pocket expenses and productivity loss, both statistically non-significant, in favour of UDCA prophylaxis. The probability of UDCA prophylaxis being cost-effective was at least 0.872. CONCLUSION: UDCA prophylaxis after RYGB in patients without gallstones before surgery was cost-effective.

Ursodeoxycholic acid for the prevention of gallstones and subsequent cholecystectomy after bariatric surgery: a meta-analysis of randomized controlled trials.

BACKGROUND: This meta-analysis aimed to compare the incidence of gallstone formation, subsequent biliary disease and the need for cholecystectomy in untreated patients and patients treated with ursodeoxycholic acid (UDCA) following bariatric surgery. METHODS: Randomized controlled trials (RCTs) comparing UDCA and controls for the prevention of gallstone formation after bariatric surgery published until February 2022 were selected and subjected to a systematic review and meta-analysis. Articles were searched in the MEDLINE, Web of Science and Cochrane Trials Register databases. Meta-analysis was performed with Review Manager 5.0. RESULTS: Eleven randomized controlled studies were included, with a total of 2363 randomized patients and 2217 patients analysed in the UDCA group versus 1415 randomized patients and 1257 patients analysed in the control group. Considering analysed patients, prophylactic use of UDCA was significantly associated with decreased (i) gallstone formation (OR = 0.25, 95% CI = 0.21-0.31), (ii) symptomatic gallstone disease (GD) (OR = 0.29, 95% CI = 0.20-0.42) and consequently (iii) cholecystectomy rate (OR = 0.33, 95% CI = 0.20-0.55). The results were similar in ITT analysis, in the subgroup of patients undergoing sleeve gastrectomy or considering only randomized versus placebo studies. CONCLUSIONS: Prophylactic use of UDCA after bariatric surgery prevents both gallstone formation and symptomatic GD and reduces the need for cholecystectomy.

Effect of ursodeoxycholic acid on gallstone formation after bariatric surgery: An updated meta-analysis.

OBJECTIVE: Bariatric surgery increases the risk of postoperative gallstone formation. Many studies have proposed ursodeoxycholic acid (UDCA) as a preventive agent for postoperative gallstone formation. This study aimed to investigate the effect of UDCA on gallstone formation after bariatric surgery in patients without preoperative gallstones. METHODS: PubMed, the Web of Science, the Cochrane Library, and EBSCO were searched for articles assessing the effect of UDCA on gallstone formation after bariatric surgery. The outcome was the incidence of postoperative gallstones. Odds ratios were used to assess dichotomous variables, and random-effects models were used for statistical analyses. RESULTS: A total of 18 studies including 4,827 participants met the inclusion criteria. The statistical results showed that the incidence of gallstones in the UDCA group was significantly lower than in the control group. Furthermore, the occurrence of symptomatic gallstones and cholecystectomy was significantly reduced. CONCLUSIONS: In patients without preoperative gallstones, UDCA can effectively prevent the formation of gallstones after bariatric surgery. In addition, UDCA can significantly reduce the occurrence of symptomatic gallstones and the risk of postoperative cholecystectomy. Doses of 500 to 600 mg/d can be used as a measure to prevent postoperative gallstone formation.

Probiotics for gallstone prevention in patients with bariatric surgery: A prospective randomized trial.

BACKGROUND: Gall stone disease was known to increase after bariatric surgery. Ursodeoxycholic acid (UDCA) might reduce the gallstone formation rate after bariatric surgery. However, other option for gallstone prevention was unclear. We reported the result of a randomized trial comparing the gallstone prevention efficacy of probiotics and digestive enzyme versus UDCA. METHODS: This prospective, randomized trial was held in an institute of Taiwan. Patients were eligible for inclusion if their body-mass index (BMI) was 32.5 kg/m2 or higher with the presence of comorbidity, or 27.5 kg/mw or higher with not-well controlled type 2 diabetes, and were aged 18-65 years. Participant were randomized assigned (1:1:1) to probiotic, digestive enzyme or UDCA. The primary endpoint was assessed in the incidence of gallstone disease at 6 months after surgery. This study is registered with ClinicalTrials.gov. number NCT03247101, and is now completed. RESULTS: From January 2016 to December 2018, of 186 patients screened for eligibility, 152 were randomly assigned to probiotic (52) or digestive enzyme (52) or UDCA (52). In the per-protocol population, mean age was 35.9 years (SD 10.6), mean BMI was 40.3 kg/m2 (SD 6.9), 57(58.2%) were female. After 6 months, the incidence of gall bladder diseased was 15.2%, in the probiotics group, 17.6% in UDCA group and 29.1% in digestive enzyme groups, confirming non-inferiority of probiotic (p = 0.38). Female gender was identified as a risk factor for gall bladder disease after bariatric surgery (odds ratio = 4.61, 95% confidence interval = 1.05, 20.3, p = 0.04). The poor drug compliance rate was 19.5%, 22.7% and 26.2% in probiotics, UDCA and digestive enzyme group respectively. UDCA group had a higher drug adverse effect than probiotic group (15.9% vs. 2.4%, p = 0.03). CONCLUSION: Probiotic is not inferior to UDCA regarding gall bladder disease prevention after bariatric surgery at 6 months.

Risk Factors for Symptomatic Gallstone Disease and Gallstone Formation After Bariatric Surgery.

PURPOSE: Patients who undergo bariatric surgery are at risk for developing cholesterol gallstones. We aimed to identify risk factors that are associated with symptomatic gallstone disease and gallstone formation after bariatric surgery. MATERIALS AND METHODS: We included participants of the UPGRADE trial, a multicenter randomized placebo-controlled trial on the prevention of symptomatic gallstone disease with ursodeoxycholic acid (UDCA) after bariatric surgery. The association between patient characteristics and symptomatic gallstone disease, and gallstone formation was evaluated using logistic regression analysis. RESULTS: Of 959 patients, 78 (8%) developed symptomatic gallstone disease within 24 months. Risk factors were the presence of a pain syndrome (OR 2.07; 95% CI 1.03 to 4.17) and asymptomatic gallstones before surgery (OR 3.15; 95% CI 1.87 to 5.33). Advanced age (OR 0.95; 95% CI 0.93 to 0.97) was protective, and UDCA prophylaxis did not reach statistical significance (OR 0.64; 95% CI 0.39 to 1.03). No risk factors were identified for gallstone formation, whereas advanced age (OR 0.98; 95% CI 0.96 to 1.00), statin use (OR 0.42; 95% CI 0.20 to 0.90), and UDCA prophylaxis (OR 0.47; 95% CI 0.30 to 0.73) all reduced the risk. CONCLUSION: Young patients with a preoperative pain syndrome and/or asymptomatic gallstones before bariatric surgery are at increased risk for symptomatic gallstone disease after surgery. Whether statins, either alone or in combination with UDCA prophylaxis, can further reduce the burden of gallstones after bariatric surgery should be investigated prospectively.

Effects of Coffee on the Gastro-Intestinal Tract: A Narrative Review and Literature Update.

The objective of the present research was to review the state of the art on the consequences of drinking coffee at the different levels of the gastrointestinal tract. At some steps of the digestive process, the effects of coffee consumption seem rather clear. This is the case for the stimulation of gastric acid secretion, the stimulation of biliary and pancreatic secretion, the reduction of gallstone risk, the stimulation of colic motility, and changes in the composition of gut microbiota. Other aspects are still controversial, such as the possibility for coffee to affect gastro-esophageal reflux, peptic ulcers, and intestinal inflammatory diseases. This review also includes a brief summary on the lack of association between coffee consumption and cancer of the different digestive organs, and points to the powerful protective effect of coffee against the risk of hepatocellular carcinoma. This review reports the available evidence on different topics and identifies the areas that would most benefit from additional studies.

Ursodeoxycholic acid for the prevention of gall stones after laparoscopic sleeve gastrectomy: a prospective controlled study.

BACKGROUND: Obesity is a risk factor for cholelithiasis. Besides, rapid weight loss after bariatric surgery upsurges the rate of cholelithiasis and acute cholecystitis. This study aimed to compare gallstone development frequency after LSG under ursodeoxycholic acid (UDCA) prophylaxis. METHODS: This prospective controlled study included 332 patients scheduled for LSG randomized to receive 500 mg UDCA daily for 12 months (UDCA Group) or no treatment (Control Group). Ultrasonography was done 6 and 12 months after surgery to detect gallstones. Cholecystectomy was done for complicated cases of cholelithiasis. RESULTS: Seventy-one patients were lost to follow-up, and 3 developed severe adverse effects of UDCA and excluded. Data are presented for 130 patients in the UDCA group and 128 in the Control group. Collectively, 11 patients (8.5%) of the UDCA group and 41 (32.0%) of the Control group developed gall stones during the first postoperative year (p < 0.001). Cholecystectomy was indicated in 3 patients (2.3%) of the UDCA group and 9 (7.0%) of the Control group (p = 0.072). On multivariate analysis, higher BMI, dyslipidemia, and lacking UDCA prophylaxis were the independent factors significantly associated with stone development. Also, stone development was associated with higher weight loss after 6 and 12 months. CONCLUSION: UDCA 500 mg once daily for 12 months after LSG is effective in reducing gallstone formation at 1 year. UDCA administration reduced the frequency of cholecystectomies from 7 to 2.3%. High BMI and dyslipidemia are the independent preoperative factors significantly associated with stone development.

The impact of ursodeoxycholic acid on gallstone disease after bariatric surgery: a meta-analysis of randomized control trials.

BACKGROUND: Ursodeoxycholic acid (UDCA) is a bile acid that has been shown to reduce the formation of gallstones after significant weight loss. OBJECTIVE: This study aimed to evaluate the impact of UDCA on the incidence of gallstones after bariatric surgery. SETTINGS: An electronic search of PubMed (Medline), Cochrane Central Register of Controlled Studies (CENTRAL), Scopus (Elsevier) databases, EMBASE, CINAHL, Clinicaltrials.gov, and Web of Science. METHODS: A meta-analysis of randomized control trials was performed. The primary outcome was the incidence of gallstones after bariatric surgery. Secondary outcomes included type of operation and time interval to and characteristics associated with gallstone formation. RESULTS: Ten randomized control trials including 2583 patients were included, 1772 patients (68.6%) receiving UDCA and 811 (31.4%) receiving placebo. There was a significant reduction in gallstone formation in patients who received UDCA postoperatively (risk ratio [RR] .36, 95% confidence interval [CI] .22-.41, P < .00001). The overall prevalence of gallstone formation was 24.7% in the control group compared to 7.3% in the UDCA group. A dose of ≤600 mg/day had a significantly reduced risk of gallstone formation compared to the placebo group (risk ratio .35; 95% CI .24-.53; P < .001). The risk reduction was not significant for the higher dose (>600 mg/day) group (risk ratio .30; 95% CI, .09-1.01, P = .05). CONCLUSIONS: UDCA significantly reduces the risk of both asymptomatic and symptomatic gallstones after bariatric surgery. A dose of 600 mg/day is associated with improved compliance and better outcomes regardless of type of surgery. UDCA should be considered part of a standard postoperative care bundle after bariatric surgery.

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.

miRNA-223 Suppresses Mouse Gallstone Formation by Targeting Key Transporters in Hepatobiliary Cholesterol Secretion Pathway.

miRNA-223 has been previously reported to play an essential role in hepatic cholesterol homeostasis. However, its role in regulation of biliary cholesterol secretion and gallstone formation remains unknown. Hence, mice with conventional knockout (KO), hepatocyte-specific knockout (ΔHepa) / knockdown (KD) or gain expression of miRNA-223 were included in the study and were subjected to lithogenic diet (LD) for various weeks. The gall bladders and liver tissues were harvested for cholesterol crystal imaging, gallstone mass measurement and molecular analysis. Levels of cholesterol, bile salt, phospholipids, and triglyceride were determined in serum, liver tissues, and bile by enzyme color reactive assays. A 3' UTR reporter gene assay was used to verify the direct target genes for miRNA-223. LD-induced gallstone formation was remarkably accelerated in miRNA-223 KO, ΔHepa, and KD mice with concurrent enhancement in total cholesterol levels in liver tissues and bile. Key biliary cholesterol transporters ABCG5 and ABCG8 were identified as direct targets of miRNA-223. Reversely, AAV-mediated hepatocyte-specific miRNA-223 overexpression prevented gallstone progression with reduced targets expression. Therefore, the present study demonstrates a novel role of miRNA-223 in the gallstone formation by targeting ABCG5 and ABCG8 and elevating miRNA-223 would be a potentially novel approach to overcome the sternness of cholesterol gallstone disease.