Effects of ursodeoxycholic acid and aspirin on the formation of lithogenic bile and gallstones during loss of weight

Liver biopsy for assessment of suspected drug-induced liver injury in metabolic dysfunction-associated steatohepatitis clinical trials: Expert consensus from the Liver Forum

BACKGROUND

Causality assessment of suspected drug-induced liver injury (DILI) during metabolic dysfunction-associated steatohepatitis (MASH) clinical trials can be challenging, and liver biopsies are not routinely performed as part of this evaluation. While the field is moving away from liver biopsy as a diagnostic and prognostic tool, information not identified by non-invasive testing may be provided on histology.

AIM

To address the appropriate utilisation of liver biopsy as part of DILI causality assessment in this setting.

METHODS

From 2020 to 2022, the Liver Forum convened a series of webinars on issues pertaining to liver biopsy during MASH trials. The Histology Working Group was formed to generate a series of consensus documents addressing these challenges. This manuscript focuses on liver biopsy as part of DILI causality assessment.

RESULTS

Expert opinion, guidance and recommendations on the role of liver biopsy as part of causality assessment of suspected DILI occurring during clinical trials for a drug(s) being developed for MASH are provided. Lessons learned from prior MASH programs are reviewed and gaps identified.

CONCLUSIONS

Although there are no pathognomonic features, histologic evaluation of suspected DILI during MASH clinical trials may alter patient management, define the pattern and severity of injury, detect findings that favour a diagnosis of DILI versus MASH progression, identify prognostic features, characterise the clinicopathological phenotype of DILI, and/or define lesions that influence decisions about trial discontinuation and further development of the drug.

Incidence of symptomatic gallstones after bariatric surgery: the impact of expectant management

BACKGROUND

Bariatric surgery is the most effective treatment for sustained weight reduction and obesity-related comorbidities. The development of gallstones as a result of rapid weight loss is a well-known consequence of bariatric procedures. It remains unclear, if there is an increased risk of these gallstones becoming symptomatic.

METHODS

A retrospective analysis of 505 consecutive patients submitted to either Roux-en-Y Gastric Bypass or Sleeve Gastrectomy between January and December 2019 was performed. The aim of our study was to determine the incidence of symptomatic cholelithiasis in asymptomatic patients with their gallbladder in situ after bariatric surgery and to identify potential risk factors for its development.

RESULTS

Of the 505 patients included, 79 (15.6%) underwent either previous cholecystectomy. (n = 67, 84.8%) or concomitant cholecystectomy during bariatric surgery (n = 12, 15.2%). Among the remaining 426 (84.4%) patients, only 8 (1.9%) became symptomatic during the 12-month follow-up period. When compared with patients who remained asymptomatic, they had a higher median preoperative BMI (47.0 vs. 42.8, p = 0.046) and prevalence of cholelithiasis on preoperative ultrasound (62.5% vs. 10.7%, p = 0.001). Multivariate analysis revealed preoperative BMI and cholelithiasis on preoperative ultrasound as independent risk factors for symptomatic biliary disease (OR 1.187, 95%CI 1.025-1.376, p = 0.022 and OR 10.720, 95%CI 1.613-71.246, p = 0.014, respectively).

CONCLUSION

Considering a low incidence of symptomatic gallstones after bariatric surgery, concomitant cholecystectomy should only be performed in symptomatic patients undergoing bariatric surgery. Preoperative factors, such as a higher BMI and positive ultrasound for cholelithiasis, may be related to the development of symptomatic gallstones.

Prevention of Gallstones After Bariatric Surgery using Ursodeoxycholic Acid: A Narrative Review of Literatures

Obesity by itself is a factor in the development of gallstone disease, and periods of weight loss after bariatric surgery further increase the risk of gallstone formation. In patients with obesity, hypersecretion of cholesterol may increase the risk of gallstone formation, which is approximately five-fold higher than that in the general population. The incidence of gallstone formation after bariatric surgery is 10-38% and often associated with a proportional increase in the risk of developing biliary complications. Routine postoperative administration of ursodeoxycholic acid (UDCA) is recommended to prevent gallstone formation. Several randomized trials have indicated that UDCA can effectively prevent gallstones and reduce the risk of cholecystectomy after bariatric procedures. The effective daily dose of UDCA in each study ranged from 500 to 1,200 mg, and it may be considered at least during the period of rapid weight loss (first 3-6 months postoperatively) to decrease the incidence of symptomatic gallstones.

Acetylsalicylic acid for metal stent in malignant distal common bile duct obstruction: A randomized controlled trial

BACKGROUND

Endoscopic biliary drainage is the treatment of choice for patients with malignant distal common bile duct obstruction. Self-expandable metal stents have clinical advantages including an increased duration of patency that may be prolonged by acetylsalicylic acid (ASA) use. The aim of this study was to investigate whether ASA had a positive effect on the patency of self-expandable metal stents compared with placebo.

METHODS

This prospective, multicenter, double-blinded, and randomized placebo-controlled trial was conducted from October 2017 to May 2020 in Korea. Patients who underwent palliative endoscopic biliary drainage with self-expandable metal stents for malignant distal bile duct obstruction were enrolled, and allocated to ASA treatment or placebo. The study outcomes were the rate of stent dysfunction at 6 months, duration of stent patency, risk factors for stent dysfunction, and any adverse events.

RESULTS

Interim analysis included 24 and 28 patients in the ASA and placebo groups, respectively. There was no significant difference between the ASA and placebo groups in stent dysfunction (25.0% vs. 20.7%, P = 0.761) or the duration of stent patency (150.97 ± 10.55 vs. 158.07 ± 8.70 days, P = 0.497). Six patients experienced suspected ASA-related adverse events, and there was one lethal case.

CONCLUSIONS

ASA did not prolong stent patency. This study was terminated early because of the possibility of serious adverse events related to ASA treatment of these patients receiving palliative care.

Management of biliary stones in bariatric surgery

Morbidly obese and post-bariatric surgery patients are at increased risk for biliary stones formation. The complications related to biliary stones may impose complexity on their management. This study aimed to review the management of biliary conditions in obese and bariatric patients. In this study, a narrative review was performed of the medical, surgical, and endoscopic procedures for the management of biliary stones and their related complications. Knowing the main prophylactic and therapeutic interventions options is essential for clinicians to properly manage the biliary stones in patients candidates or submitted to bariatric surgery.

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.

Excess Body Weight and Gallstone Disease

Background

Approximately one fifth of adults are diagnosed with gallstones worldwide. Of these, around 25% develop gallstone disease (indicated by the presence of symptoms) and undergo cholecystectomy.

Summary

The risk of gallstones is influenced by a combination of genetic and lifestyle factors, such as excess body weight. In fact, body mass has been demonstrated to be a major risk factor for symptomatic gallstones. Rapid weight loss can also initiate a prolithogenic state and further increase the likelihood of either gallstone formation or existing gallstones becoming symptomatic; however, sensible weight loss strategies can mitigate this risk. This review discusses the role of excess body weight and the risk of gallstone disease, as well as the options available for the prevention of symptomatic gallstones.

Key Messages

Healthy weight loss diets combined with regular physical activity can promote successful weight loss and weight maintenance and reduce the risk of gallstones. Should rapid weight loss be required for health reasons or be expected, e.g., after bariatric surgery, prophylactic ursodeoxycholic acid during the period of weight reduction has been demonstrated to reduce the incidence of gallstones formation or symptomatic gallstone occurrence. The recent German guidelines on gallstones recommend simultaneous cholecystectomy during bariatric surgery but only for those with preexisting symptomatic stones.

Statement on additional scientific evidence in relation to the essential composition of total diet replacement for weight control

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to revise the Opinion on the essential composition of total diet replacements for weight control (TDRs) regarding the minimum content of linoleic acid (LA) and alpha-linolenic acid (ALA) and the maximum content of magnesium (Mg). Through a comprehensive literature search, human studies were retrieved reporting on LA and ALA concentrations in adipose tissue (AT), on weight loss and gallstone formation following TDR consumption and on diarrhoea after supplemental Mg intake. The distribution of the amount of LA and ALA release from AT during weight loss when consuming TDRs was estimated using statistical simulations. Using the fifth percentile, the coverage of the adequate intake (AI) for both FA was estimated. For the risk of developing diarrhoea when consuming TDRs with an Mg content of 350 mg/day, four cross-over studies using 360-368 mg Mg/day were reviewed. The Panel concludes that (1) there is no need to add LA to TDRs, as the amount released from AT during weight loss when consuming TDRs is sufficient to cover the AI for LA; (2) a minimum of 0.8 g/day ALA is needed in TDRs in order to meet the AI for ALA; (3) the minimum fat content of TDRs of 20 g/day as derived in the Panel's previous opinion is proposed to be maintained until the availability of further evidence, given the considerable uncertainty as to the amount of fat required for reducing the risk of gallstone formation; and (4) the likelihood that Mg-induced diarrhoea occurs at a severity that may be considered of concern for overweight and obese individuals consuming TDRs is low when the total maximum Mg content in TDRs is 350 mg/day.

Acute Cholecystitis Following Allogeneic Hematopoietic Stem Cell Transplantation: Clinical Features, Outcomes, Risk Factors, and Prediction Model

Acute cholecystitis (AC) is a potentially fatal complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT); however, only limited information is available on its clinical features, outcomes, and risk management strategies. This retrospective, nested, case-control study included 6701 patients undergoing allo-HSCT at our center from January 2004 to June 2019. In total, 72 patients (1.1%) were diagnosed with AC; among these, acute acalculous cholecystitis had a slightly higher prevalence (42 patients, 58.3%). Patients with moderate and severe AC exhibited remarkably worse overall survival (P = .001) and non-relapse mortality (P = .011) than others. Survival of haploidentical HSCT recipients with AC was comparable to that for patients with human leukocyte antigen (HLA)-identical donors. Age ≥ 18 years, antecedent stage II to IV acute graft-versus-host disease, and total parenteral nutrition were identified as potential risk factors for AC following allo-HSCT, while haploidentical transplantations were not more susceptible to AC than HLA-identical HSCT. Based on these criteria, a risk score model was developed and validated to estimate the probability of AC following allo-HSCT. The model separates all patients into low-, intermediate-, and high-risk groups and thereby provides a basis for early detection of this complication in the management of allo-HSCT.

Aspirin for metal stent in malignant distal common bile duct obstruction (AIMS): study protocol for a multicenter randomized controlled trial

Background

Endoscopic retrograde biliary drainage (ERBD) is the treatment of choice for patients with malignant distal common bile duct (CBD) obstruction. Self-expandable metal stents (SEMS), which are commonly used in unresectable cases, have many clinical advantages, including longer stent patency. Although the expected patency of SEMS is around 8 months, it has recently been reported that the duration of SEMS’ patency in patients using aspirin is prolonged. Our study, therefore, aims to investigate the effect of aspirin on SEMS’ patency.

Methods/design

This is an investigator-initiated, prospective, multicenter, double-blind, randomized placebo-controlled trial that will be conducted from November 2017 in four tertiary centers in South Korea. We intend to include in our study 184 adult (aged ≥ 20 years) patients with malignant distal CBD obstruction for whom ERBD with SEMS was successfully performed. The patients will be randomly allocated to two groups, which will comprise patients who have either taken 100 mg aspirin or a placebo for 6 months after index ERBD. The primary outcome will be the rate of stent dysfunction, and the secondary outcomes will be the duration of patency, the rate of reintervention, and the occurrence of adverse events.

Discussion

The aspirin for metal stents in malignant distal common bile duct obstruction (AIMS) study should determine the efficacy of aspirin in maintaining metal-stent patency in patients with malignant distal CBD obstructive.

Trial registration

ClinicalTrials.gov, ID: NCT03279809. Registered on 5 September 2017.

Effects of Diets on Adipose Tissue

BACKGROUND

Obesity is a major health problem that has become a global epidemic. Overweight and obesity are commonly associated with the development of several pathologies, such as insulin resistance, cardiovascular diseases, sleep apnea and several types of cancer, which can lead to further morbidity and mortality. An increased abdominal adiposity renders overweight and obese individuals more prone to metabolic and cardiovascular problems.

OBJECTIVE

This Review aims to describe the dietary strategies to deal with excess adiposity given the medical, social and economic consequences of obesity.

METHODS

One hundred and eighty-five papers were included in the present Review.

RESULTS

Excess adiposity leads to several changes in the biology, morphology and function of the adipose tissue, such as adipocyte hypertrophy and hyperplasia, adipose tissue inflammation and fibrosis and an impaired secretion of adipokines, contributing to the onset of obesity- related comorbidities. The first approach for obesity management and prevention is the implementation of a diet combined with physical activity. The present review summarizes the compelling evidence showing body composition changes, impact on cardiometabolism and potential adverse effects of very-low calorie, low- and high-carbohydrate, high-protein or low-fat diets. The use of macronutrients during the preprandial and postprandial state has been also reviewed to better understand the metabolic changes induced by different dietary interventions.

CONCLUSION

Dietary changes should be individualised, tailored to food preferences and allow for flexible approaches to reducing calorie intake in order to increase the motivation and compliance of overweight and obese patients.

Update on the Molecular Mechanisms Underlying the Effect of Cholecystokinin and Cholecystokinin-1 Receptor on the Formation of Cholesterol Gallstones

Cholecystokinin (CCK) is an important neuro-intestinal peptide hormone produced by the enteroendocrine I-cells in the upper part of small intestine. Protein- and fat-enriched food plays an important role in triggering CCK secretion from the intestine. Carbohydrates stimulate only small amounts of CCK release. The CCK-1 receptor (CCK-1R) is largely localized in the gallbladder, sphincter of Oddi, pancreas, small intestine, gastric mucosa, and pyloric sphincter, where it is responsible for CCK to regulate multiple digestive processes including gallbladder contraction, pancreatic secretion, small intestinal transit, and gastric emptying. Accumulated evidence clearly demonstrates that CCK regulates gallbladder and small intestinal motility through CCK-1R signaling cascade and the effect of CCK-1R on small intestinal transit is a physiological response for regulating intestinal cholesterol absorption. Disruption of the Cck or the Cck-1r gene in mice significantly increases the formation of cholesterol gallstones by disrupting gallbladder emptying and biliary cholesterol metabolism, as well as promoting intestinal absorption of cholesterol. Abnormalities in gallbladder motility function in response to exogenously administered CCK are found primarily in patients with cholesterol gallstones. Patients with pigment gallstones display an intermediate degree of gallbladder motility defect without gallbladder inflammation and enlarged fasting gallbladder. Dysfunctional gallbladder contractility has been found under several conditions such as pregnancy, obesity, diabetes, celiac disease, and total parenteral nutrition although gallstones are not observed. The gallbladder-specific CCK-1R-selective agonist may lead to an efficacious novel way for preventing gallstone formation by promoting gallbladder emptying, particularly for pregnant women and subjects with dysfunctional gallbladder motility function such as celiac patients, as well as patients with total parenteral nutrition.

Risk of cholecystectomy in morbidly obese patients after bariatric surgery in Taiwan

PURPOSE

The anatomic rearrangement of the gastrointestinal tract after bariatric surgery may result in alterations in the bile acid pool and consequently, gallstone disease. We aimed to investigate whether patients undergoing bariatric surgery are at risk of developing gallbladder disease postoperatively.

PATIENTS AND METHODS

We conducted a population-based cohort study by using claims data from the Taiwan National Health Insurance Research Database. The study cohort comprised 4197 patients diagnosed with morbid obesity.

RESULTS

Among the morbidly obese patients, 2698 underwent bariatric surgery. Females and younger subjects were more prevalent in the surgical group than non-surgical group. Bariatric surgery reduced all obesity-related comorbidities. Cox proportional hazards regression was performed, which revealed increased risk of cholecystectomy after bariatric surgery among obese patients (adjusted hazard ratio, 3.43; p=0.0165). After adjusting for sex and age, the incidence of cholecystectomy was increased in the females population (adjusted hazard ratio, 3.74; p<0.05) and in 30-64 years-old-group (adjusted hazard ratio: 3.69, p<0.05). The cumulative incidence rate of cholecystectomy showed an increased tendency in those undergoing bariatric surgery by log-rank test.

CONCLUSION

Based on the Taiwan database population-based cohort study, bariatric surgery increases the risk of cholecystectomy among morbidly obese patients, especially in the female population and patients aged 30-64 years.

The Role of Diet in the Pathogenesis of Cholesterol Gallstones

Cholesterol gallstone disease is a major health problem in Westernized countries and depends on a complex interplay between genetic factors, lifestyle and diet, acting on specific pathogenic mechanisms. Overweigh, obesity, dyslipidemia, insulin resistance and altered cholesterol homeostasis have been linked to increased gallstone occurrence, and several studies point to a number of specific nutrients as risk- or protective factors with respect to gallstone formation in humans. There is a rising interest in the identification of common and modifiable dietetic factors that put the patients at risk of gallstones or that are able to prevent gallstone formation and growth. In particular, dietary models characterized by increased energy intake with highly refined sugars and sweet foods, high fructose intake, low fiber contents, high fat, consumption of fast food and low vitamin C intake increase the risk of gallstone formation. On the other hand, high intake of monounsaturated fats and fiber, olive oil and fish (ω-3 fatty acids) consumption, vegetable protein intake, fruit, coffee, moderate alcohol consumption and vitamin C supplementation exert a protective role. The effect of some confounding factors (e.g., physical activity) cannot be ruled out, but general recommendations about the multiple beneficial effects of diet on cholesterol gallstones must be kept in mind, in particular in groups at high risk of gallstone formation.

Similarities and differences between biliary sludge and microlithiasis: Their clinical and pathophysiological significances

The terms biliary sludge and cholesterol microlithiasis (hereafter referred to as microlithiasis) were originated from different diagnostic techniques and may represent different stages of cholesterol gallstone disease. Although the pathogenesis of biliary sludge and microlithiasis may be similar, microlithiasis could be preceded by biliary sludge, followed by persistent precipitation and aggregation of solid cholesterol crystals, and eventually, gallstone formation. Many clinical conditions are clearly associated with the formation of biliary sludge and microlithiasis, including total parenteral nutrition, rapid weight loss, pregnancy, organ transplantation, administration of certain medications, and a variety of acute and chronic illnesses. Numerous studies have demonstrated complete resolution of biliary sludge in approximately 40% of patients, a cyclic pattern of disappearing and reappearing in about 40%, and progression to gallstones in nearly 20%. Although only a minority of patients with ultrasonographic demonstration of biliary sludge develop gallstones, it is still a matter of controversy whether microlithiasis could eventually evolve to cholesterol gallstones. Biliary sludge and microlithiasis are asymptomatic in the vast majority of patients; however, they can cause biliary colic, acute cholecystitis, and acute pancreatitis. Biliary sludge and microlithiasis are most often diagnosed ultrasonographically and bile microscopy is considered the gold standard for their diagnosis. Specific measures to prevent the development of biliary sludge are not practical or cost-effective in the general population. Laparoscopic cholecystectomy offers the most definitive therapy on biliary sludge. Endoscopic sphincterotomy or surgical intervention is effective for microlithiasis-induced pancreatitis. Ursodeoxycholic acid can effectively prevent the recurrence of solid cholesterol crystals and significantly reduce the risk of recurrent pancreatitis.

Ursodeoxycholic Acid in the Prevention of Gallstone Formation After Bariatric Surgery: an Updated Systematic Review and Meta-analysis

We aim to review the available literature on obese patients treated with ursodeoxycholic acid (UDCA) in order to prevent gallstone formation after bariatric surgery. A systematic literature search was performed in PubMed, Cochrane library, and Scopus databases, in accordance with the PRISMA guidelines. Eight studies met the inclusion criteria incorporating 1355 patients. Random-effects meta-analysis showed a lower incidence of gallstone formation in patients taking UDCA. Subgroup analysis reported fewer cases of gallstone disease in the UDCA group in relation to different bariatric procedures, doses of administered UDCA, and time from bariatric surgery. Adverse events were similar in both groups. Fewer patients required cholecystectomy in UDCA group. No deaths were reported. The administration of UDCA after bariatric surgery seems to prevent gallstone formation.

Treatment options for nonalcoholic steatohepatitis - a safety evaluation

INTRODUCTION

There is an urgent as yet unmet need to develop highly effective and safe therapeutics for nonalcoholic fatty liver disease (NAFLD). The remarkable progress in understanding NAFLD pathogenesis allowed the identification of injury pathways which may be recruited as therapy targets. Areas covered: This article reviews the safety and tolerability data of the NAFLD therapies and explains the mechanistic basis for each of the established and investigational drugs. Treatment targets include: weight loss, anti-metabolic agents such as lipid lowering and anti-diabetic drugs, inflammation, fibrosis and others such as targeting gut microbiota, immune modulation and apoptosis. Expert opinion: Current therapies continue to remain suboptimal. Weight loss is effective but hard to achieve. Traditional and endoscopic bariatric procedures are promising although more randomized trials are needed and the long-term safety remains to be established. Clinical trials have demonstrated the efficacy of several drugs for the treatment of NASH. Of these, there remains some uncertainty about the long-term safety of vitamin E. Pioglitazone is associated with osteopenia, fluid retention and weight gain. Obeticholic acid causes pruritus in a substantial proportion of subjects and elafibranor has been associated with transient rises in creatinine. Several exciting therapies are under development and results of clinical and post-marketing trials will help elucidate their safety.

Preventing a Mass Disease: The Case of Gallstones Disease: Role and Competence for Family Physicians

Gallstone formation is the result of a complex interaction between genetic and nongenetic factors. We searched and reviewed the available literature to define how the primary prevention of gallstones (cholesterol gallstones in particular) could be applied in general practice. Electronic bibliographical databases were searched. Prospective and retrospective cohort studies and case-controlled studies were analyzed and graded for evidence quality. The epidemiological data confirmed that genetic factors are estimated to account for only approximately 25% of the overall risk of gallstones, while metabolic/environmental factors are at least partially modifiable in stone-free risk groups, and are thus modifiable by primary prevention measures related to diet, lifestyle, and environmental factors (i.e., rapid weight loss, bariatric surgery, somatostatin or analogues therapy, transient gallbladder stasis, and hormone therapy). There is no specific recommendation for the secondary prevention of recurrent gallstones. Family physicians can contribute to preventing gallstones due to their capability to identify and effectively manage several risk factors discussed in this study. Although further studies are needed to better elucidate the involvement of epigenetic factors that may regulate the effect of environment and lifestyle on gene expression in the primary prevention of gallstone formation, preventive interventions are feasible and advisable in the general practice setting.

Gallstones

Gallstones grow inside the gallbladder or biliary tract. These stones can be asymptomatic or symptomatic; only gallstones with symptoms or complications are defined as gallstone disease. Based on their composition, gallstones are classified into cholesterol gallstones, which represent the predominant entity, and bilirubin ('pigment') stones. Black pigment stones can be caused by chronic haemolysis; brown pigment stones typically develop in obstructed and infected bile ducts. For treatment, localization of the gallstones in the biliary tract is more relevant than composition. Overall, up to 20% of adults develop gallstones and >20% of those develop symptoms or complications. Risk factors for gallstones are female sex, age, pregnancy, physical inactivity, obesity and overnutrition. Factors involved in metabolic syndrome increase the risk of developing gallstones and form the basis of primary prevention by lifestyle changes. Common mutations in the hepatic cholesterol transporter ABCG8 confer most of the genetic risk of developing gallstones, which accounts for ∼25% of the total risk. Diagnosis is mainly based on clinical symptoms, abdominal ultrasonography and liver biochemistry tests. Symptoms often precede the onset of the three common and potentially life-threatening complications of gallstones (acute cholecystitis, acute cholangitis and biliary pancreatitis). Although our knowledge on the genetics and pathophysiology of gallstones has expanded recently, current treatment algorithms remain predominantly invasive and are based on surgery. Hence, our future efforts should focus on novel preventive strategies to overcome the onset of gallstones in at-risk patients in particular, but also in the population in general.

The inflammatory inception of gallbladder cancer

Gallbladder cancer is a lethal disease with notable geographical variations worldwide and a predilection towards women. Its main risk factor is prolonged exposure to gallstones, although bacterial infections and other inflammatory conditions are also associated. The recurrent cycles of gallbladder epithelium damage and repair enable a chronic inflammatory environment that promotes progressive morphological impairment through a metaplasia-dysplasia-carcinoma, along with cumulative genome instability. Inactivation of TP53, which is mutated in over 50% of GBC cases, seems to be the earliest and one of the most important carcinogenic pathways involved. Increased cell turnover and oxidative stress promote early alteration of TP53, cell cycle deregulation, apoptosis and replicative senescence. In this review, we will discuss evidence for the role of inflammation in gallbladder carcinogenesis obtained through epidemiological studies, genome-wide association studies, experimental carcinogenesis, morphogenetic studies and comparative studies with other inflammation-driven malignancies. The evidence strongly supports chronic, unresolved inflammation as the main carcinogenic mechanism of gallbladder cancer, regardless of the initial etiologic trigger. Given this central role of inflammation, evaluation of the potential for GBC prevention removing causes of inflammation or using anti-inflammatory drugs in high-risk populations may be warranted.

Management of gallstones and its related complications

The majority of gallstone patients remain asymptomatic; however, interest toward the gallstone disease is continuing because of the high worldwide prevalence and management costs and the development of gallstone symptoms and complications. For cholesterol gallstone disease, moreover, a strong link exists between this disease and highly prevalent metabolic disorders such as obesity, dyslipidemia, type 2 diabetes, hyperinsulinemia, hypertriglyceridemia and the metabolic syndrome. Information on the natural history as well as the diagnostic, surgical (mainly laparoscopic cholecystectomy) and medical tools available to facilitate adequate management of cholelithiasis and its complications are, therefore, crucial to prevent the negative outcomes of gallstone disease. Moreover, some risk factors for gallstone disease are modifiable and some preventive strategies have become necessary to reduce the onset and the severity of complications.

Cholesterol cholelithiasis in pregnant women: pathogenesis, prevention and treatment

Epidemiological and clinical studies have found that gallstone prevalence is twice as high in women as in men at all ages in every population studied. Hormonal changes occurring during pregnancy put women at higher risk. The incidence rates of biliary sludge (a precursor to gallstones) and gallstones are up to 30 and 12%, respectively, during pregnancy and postpartum, and 1-3% of pregnant women undergo cholecystectomy due to clinical symptoms or complications within the first year postpartum. Increased estrogen levels during pregnancy induce significant metabolic changes in the hepatobiliary system, including the formation of cholesterol-supersaturated bile and sluggish gallbladder motility, two factors enhancing cholelithogenesis. The therapeutic approaches are conservative during pregnancy because of the controversial frequency of biliary disorders. In the majority of pregnant women, biliary sludge and gallstones tend to dissolve spontaneously after parturition. In some situations, however, the conditions persist and require costly therapeutic interventions. When necessary, invasive procedures such as laparoscopic cholecystectomy are relatively well tolerated, preferably during the second trimester of pregnancy or postpartum. Although laparoscopic operation is recommended for its safety, the use of drugs such as ursodeoxycholic acid (UDCA) and the novel lipid-lowering compound, ezetimibe would also be considered. In this paper, we systematically review the incidence and natural history of pregnancy-related biliary sludge and gallstone formation and carefully discuss the molecular mechanisms underlying the lithogenic effect of estrogen on gallstone formation during pregnancy. We also summarize recent progress in the necessary strategies recommended for the prevention and the treatment of gallstones in pregnant women.

Obesity and the risk and prognosis of gallstone disease and pancreatitis

Obesity is a risk factor for the formation of cholesterol gallstones and exposes patients to increased risk of gallstone-related complications and cholecystectomy. Rapid weight loss achieved by very low calorie diets or bariatric surgery is also a risk factor for cholelithiasis in obese patients, and therapy should take into account the higher prevalence of gallstones, the possibility of more frequent complications and the need for prophylactic treatment with oral ursodeoxycholic acid during weight loss. Obesity is also frequent in children and adolescents, and the burden of cholesterol cholelithiasis is increasing in this population. The chance to develop acute pancreatitis and the severity of the disease are higher in obese subjects because of specific pathogenic factors, including supersaturated bile and crystal formation, rapid weight loss, and visceral obesity. All health policies aimed at reducing the incidence of obesity worldwide will decrease the incidence of gallstones and gallstone-related complications. The pathophysiological scenarios and the therapeutic implications for obesity, gallstone disease, and pancreatitis are discussed.

Ursodeoxycholic acid and diets higher in fat prevent gallbladder stones during weight loss: a meta-analysis of randomized controlled trials

BACKGROUND & AIMS

The prevalence of gallstones is increasing in association with the obesity epidemic, but rapid weight loss also increases the risk of stone formation. We conducted a systematic review of the efficacy of strategies to prevent gallbladder stones in adults as they lose weight.

METHODS

Randomized controlled trials of nonsurgical strategies to prevent gallstones were identified by electronic and manual searches. Our final analysis included 13 trials, comprising 1836 participants undergoing weight loss through dieting (8 trials) or bariatric surgery (5 trials). The trials compared ursodeoxycholic acid (UDCA) or high-fat weight loss diets with control interventions. We performed random-effects meta-analyses and evaluated heterogeneity and bias with subgroup, sensitivity, regression, and sequential analysis.

RESULTS

UDCA reduced the risk of ultrasound-verified gallstones compared with control interventions (risk ratio, 0.33; 95% confidence interval [CI], 0.18-0.60; number needed to treat, 9). This effect was significantly larger in trials of diets alone (risk ratio, 0.17; 95% CI, 0.11-0.25) than in trials of patients who underwent bariatric surgery (risk ratio, 0.42; 95% CI, 0.21-0.83) (test for subgroup differences, P =.03). UDCA reduced the risk of cholecystectomy for symptomatic stones (risk ratio, 0.20; 95% CI, 0.07-0.53). Diets high in fat content also reduced gallstones, compared with those with low fat content (risk ratio, 0.09; 95% CI, 0.01-0.61). The meta-analyses were confirmed in trials with a low risk of bias but not in sequential analysis. No additional beneficial or harmful outcomes were identified.

CONCLUSIONS

On the basis of a meta-analysis of randomized controlled trials, during weight loss, UDCA and/or higher dietary fat content appear to prevent formation of gallstones.

Genetics of gallstone disease

Gallstone disease (GSD) is one of the most common biliary tract disorders worldwide. The prevalence, however, varies from 5.9-21.9% in Western society to 3.1-10.7% in Asia. Most gallstones (75%) are silent. Approximately half of symptomatic gallstone carriers experience a second episode of biliary pain within 1 year. These individuals are at increased risk of developing acute cholecystitis, acute cholangitis, and biliary pancreatitis. As can be expected, these complications burden health care systems because of their invasive nature and surgical cost. Factors that contribute to gallstone formation include supersaturation of cholesterol in bile, gallbladder hypomotility, destabilization of bile by kinetic protein factors, and abnormal mucins. Epidemiologic studies have implicated multiple environmental factors and some common genetic elements in gallstone formation. Genetic factors that influence gallstone formation have been elaborated from linkage studies of twins, families, and ethnicities. Accumulating evidence suggests that genetic factors play a role in GSD.

Risk of symptomatic gallstones and cholecystectomy after a very-low-calorie diet or low-calorie diet in a commercial weight loss program: 1-year matched cohort study

Background:

Concern exists regarding gallstones as an adverse event of very-low-calorie diets (VLCDs; <800 kcal per day).

Objective:

To assess the risk of symptomatic gallstones requiring hospital care and/or cholecystectomy in a commercial weight loss program using VLCD or low-calorie diet (LCD).

Design:

A 1-year matched cohort study of consecutively enrolled adults in a commercial weight loss program conducted at 28 Swedish centers between 2006 and 2009. A 3-month weight loss phase of VLCD (500 kcal per day) or LCD (1200–1500 kcal per day) was followed by a 9-month weight maintenance phase. Matching (1:1) was performed by age, sex, body mass index, waist circumference and gallstone history (n=3320:3320). Gallstone and cholecystectomy data were retrieved from the Swedish National Patient Register.

Results:

One-year weight loss was greater in the VLCD than in the LCD group (−11.1 versus −8.1 kg; adjusted difference, −2.8 kg, 95% CI −3.1 to −2.4; P<0.001). During 6361 person–years, 48 and 14 gallstones requiring hospital care occurred in the VLCD and LCD groups, respectively, (152 versus 44/10 000 person–years; hazard ratio, 3.4, 95% CI 1.8–6.3; P<0.001; number-needed-to-harm, 92, 95% CI 63–168; P<0.001). Of the 62 gallstone events, 38 (61%) resulted in cholecystectomy (29 versus 9; hazard ratio, 3.2, 95% CI 1.5–6.8; P=0.003; number-needed-to-harm, 151, 95% CI 94–377; P<0.001). Adjusting for 3-month weight loss attenuated the hazard ratios, but the risk remained higher with VLCD than LCD for gallstones (2.5, 95% CI 1.3–5.1; P=0.009) and became borderline for cholecystectomy (2.2, 95% CI 0.9–5.2; P=0.08).

Conclusion:

The risk of symptomatic gallstones requiring hospitalization or cholecystectomy, albeit low, was 3-fold greater with VLCD than LCD during the 1-year commercial weight loss program.

Endoscopic ultrasonography in patients with elevated carbohydrate antigen 19-9 of obscure origin

AIM: To evaluate the efficacy of endoscopic ultrasonography (EUS) in patients with elevated carbohydrate antigen (CA) 19-9 levels of obscure origin.

METHODS: Patients who had visited Pusan National University Hospital because of elevated serum CA 19-9 levels, between January 2007 and December 2009, were retrospectively enrolled. EUS had been performed on all subjects, in addition to routine blood tests, endoscopy, abdominal computed tomography (CT) and other clinical exams, which had not revealed any abnormal findings suggestive of the origin of the elevated CA 19-9 levels.

RESULTS: Of the 17 patients, gallbladder sludge was detected in 16 patients (94.1%) and common bile duct sludge was observed in 3 patients (17.6%). After the administration of ursodeoxycholic acid to 12 of the patients with gallbladder sludge, CA 19-9 levels normalized in 6 of the patients after a median of 4.5 mo.

CONCLUSION: EUS is a useful diagnostic method for patients with elevated CA 19-9 levels of obscure origin, even if the reason for abnormal levels of this serum marker cannot be determined through prior examinations, including abdominal CT.

Prevention of cholesterol gallstones by inhibiting hepatic biosynthesis and intestinal absorption of cholesterol

BACKGROUND

Cholesterol cholelithiasis is a multifactorial disease influenced by a complex interaction of genetic and environmental factors and represents a failure of biliary cholesterol homoeostasis in which the physical-chemical balance of cholesterol solubility in bile is disturbed.

DESIGN

The primary pathophysiologic event is persistent hepatic hypersecretion of biliary cholesterol, which has both hepatic and small intestinal components. The majority of the environmental factors are probably related to Western-type dietary habits, including excess cholesterol consumption.

RESULTS

Laparoscopic cholecystectomy, one of the most commonly performed surgical procedures in the United States, is nowadays a major treatment for gallstones. However, it is invasive and can cause surgical complications, and not all patients with symptomatic gallstones are candidates for surgery. The hydrophilic bile acid, ursodeoxycholic acid (UDCA), has been employed as first-line pharmacological therapy in a subgroup of symptomatic patients with small, radiolucent cholesterol gallstones. Long-term administration of UDCA can promote the dissolution of cholesterol gallstones. However, the optimal use of UDCA is not always achieved in clinical practice because of failure to titrate the dose adequately.

CONCLUSIONS

Therefore, the development of novel, effective and noninvasive therapies is crucial for reducing the costs of health care associated with gallstones. In this review, we summarize recent progress in investigating the inhibitory effects of ezetimibe and statins on intestinal absorption and hepatic biosynthesis of cholesterol, respectively, for the treatment of gallstones, as well as in elucidating their molecular mechanisms by which combination therapy could prevent this very common liver disease worldwide.

Weight loss and dropout during a commercial weight-loss program including a very-low-calorie diet, a low-calorie diet, or restricted normal food: observational cohort study

BACKGROUND

The effectiveness of commercial weight-loss programs consisting of very-low-calorie diets (VLCDs) and low-calorie diets (LCDs) is unclear.

OBJECTIVE

The aim of the study was to quantify weight loss and dropout during a commercial weight-loss program in Sweden (Itrim; cost: $1300/€1000; all participants paid their own fee).

DESIGN

This observational cohort study linked commercial weight-loss data with National Health Care Registers. Weight loss was induced with a 500-kcal liquid-formula VLCD [n = 3773; BMI (in kg/m(2)): 34 ± 5 (mean ± SD); 80% women; 45 ± 12 y of age (mean ± SD)], a 1200-1500-kcal formula and food-combination LCD (n = 4588; BMI: 30 ± 4; 86% women; 50 ± 11 y of age), and a 1500-1800-kcal/d restricted normal-food diet (n = 676; BMI: 29 ± 5; 81% women; 51 ± 12 y of age). Maintenance strategies included exercise and a calorie-restricted diet. Weight loss was analyzed by using an intention-to-treat analysis (baseline substitution).

RESULTS

After 1 y, mean (±SD) weight changes were -11.4 ± 9.1 kg with the VLCD (18% dropout), -6.8 ± 6.4 kg with the LCD (23% dropout), and -5.1 ± 5.9 kg with the restricted normal-food diet (26% dropout). In an adjusted analysis, the VLCD group lost 2.8 kg (95% CI: 2.5, 3.2) and 3.8 kg (95% CI: 3.2, 4.5) more than did the LCD and restricted normal-food groups, respectively. A high baseline BMI and rapid initial weight loss were both independently associated with greater 1-y weight loss (P < 0.001). Younger age and low initial weight loss predicted an increased dropout rate (P < 0.001). Treatment of depression (OR: 1.4; 95% CI: 1.1, 1.9) and psychosis (OR: 2.6; 95% CI: 1.1, 6.3) were associated with an increased dropout rate in the VLCD group.

CONCLUSION

A commercial weight-loss program, particularly one using a VLCD, was effective at reducing body weight in self-selected, self-paying adults.

Mucin genes in gallstone disease

Gallstone disease is a complex disorder that can be caused by environmental influences, common genetic factors and their interactions. Three major pathogenic abnormalities are considered to involve in gallstone formation: cholesterol supersaturation in bile, precipitation and nucleation of excess cholesterol, and gallbladder hypomotility, while, mucin takes part in the cholesterol nucleation process. Up to date, more than 20 mucin genes have been reported, 9 of them are identified at the mRNA and/or protein level in native gallbladder and its associated diseases. In the gallbladder, mucin is essential for best protection against detergent effect of high concentration of bile acids. Over the past decade, the properties, expressions and functions of the gallbladder mucins are delineated in animal and human studies. Alteration expressions of mucins are thought to response during the pathogenesis of gallstone formation. Moreover, recent genetic association study demonstrated mucin gene polymorphisms may also influence susceptibility to gallstone disease. This review is not to provide a complete coverage of all the aspects of mucin glycoproteins, but focus on the role and expression of mucins involve in the regulation of cholelithogenesis.

[Obesity and gallbladder diseases]

Obesity is an important health problem in the world and related to many critical diseases, such as diabetes, cardiovascular disease, and metabolic syndrome. Obesity leads to fat infiltration of multiple organs and infiltrated adipose tissue produces many cytokines resulting in the dysfunction of organs such as the gallbladder. In the biliary diseases, obesity and overweight have been known as a major risk factor for gallstones. According to current studies, obesity, insulin resistance, hyperinsulinemia, and metabolic syndrome are related to various gallbladder diseases including gallbladder stones, cholecystitis, gallbladder polyps, and gallbladder cancers. We reviewed further literature on the obesity and gallbladder diseases, in aspects of epidemiology, mechanism, pathology and prevention.

Epidemiology of gallbladder disease: cholelithiasis and cancer

Diseases of the gallbladder are common and costly. The best epidemiological screening method to accurately determine point prevalence of gallstone disease is ultrasonography. Many risk factors for cholesterol gallstone formation are not modifiable such as ethnic background, increasing age, female gender and family history or genetics. Conversely, the modifiable risks for cholesterol gallstones are obesity, rapid weight loss and a sedentary lifestyle. The rising epidemic of obesity and the metabolic syndrome predicts an escalation of cholesterol gallstone frequency. Risk factors for biliary sludge include pregnancy, drugs like ceftiaxone, octreotide and thiazide diuretics, and total parenteral nutrition or fasting. Diseases like cirrhosis, chronic hemolysis and ileal Crohn's disease are risk factors for black pigment stones. Gallstone disease in childhood, once considered rare, has become increasingly recognized with similar risk factors as those in adults, particularly obesity. Gallbladder cancer is uncommon in developed countries. In the U.S., it accounts for only ~ 5,000 cases per year. Elsewhere, high incidence rates occur in North and South American Indians. Other than ethnicity and female gender, additional risk factors for gallbladder cancer include cholelithiasis, advancing age, chronic inflammatory conditions affecting the gallbladder, congenital biliary abnormalities, and diagnostic confusion over gallbladder polyps.

Hereditary liver disease: gallstones

Gallstones are common in Western countries and due to pain and complications pose a substantial burden on health care systems. In general, cholesterol gallstones are distinguished from bilirubin gallstones. Bilirubin gallstones form if the ion product of unconjugated bilirubin and calcium in gallbladder bile exceeds the solubilisation capacities of mixed micelles and vesicles. Cholesterol gallstones develop if the amount of cholesterol in gallbladder bile exceeds the maximum concentration that is soluble at the given concentration of bile salts and phospholipids. In addition, cholesterol gallstone formation requires hypomotility of the gallbladder and a mucin gel as nucleation matrix for monohydrate crystals. The individual risk of gallstone formation is determined by interactions of lithogenic alleles of gallstone susceptibility genes and multiple environmental factors. For asymptomatic gallstones, expectant management is recommended, whereas an episode of gallstone-associated pain substantially increases the risk of complications such as cholecystitis, cholangitis and pancreatitis and therefore necessitates cholecystectomy.

Epidemiology of gallstones

Gallstones are common with prevalences as high as 60% to 70% in American Indians and 10% to 15% in white adults of developed countries. Ethnic differences abound with a reduced frequency in black Americans and those from East Asia, while being rare in sub-Saharan Africa. Certain risk factors for gallstones are immutable: female gender, increasing age, and ethnicity/family (genetic traits). Others are modifiable: obesity, the metabolic syndrome, rapid weight loss, certain diseases (cirrhosis and Crohn disease), gallbladder stasis (from spinal cord injury or drugs, such as somatostatin), and lifestyle.

The prevalence and risk factors for gallstone disease

Gallstone disease is one of the most prevalent gastrointestinal disorders. In addition, the costs associated with the diagnosis and treatment of gallstone disease have been rapidly increasing. The etiology and pathogenesis of gallstone disease remains incompletely understood. Gallstone formation may result from a complex interaction of genetic and environmental factors. This article reviews the prevalence and risk factors associated with gallstone disease. Understanding the pathogenesis of gallstone disease could lead to the development of better therapeutic and preventive strategies for dealing with this disease.

Effect of gallbladder hypomotility on cholesterol crystallization and growth in CCK-deficient mice

We investigated the effect of gallbladder hypomotility on cholesterol crystallization and growth during the early stage of gallstone formation in CCK knockout mice. Contrary to wild-type mice, fasting gallbladder volumes were enlarged and the response of gallbladder emptying to a high-fat meal was impaired in knockout mice on chow or the lithogenic diet. In the lithogenic state, large amounts of mucin gel and liquid crystals as well as arc-like and tubular crystals formed first, followed by rapid formation of classic parallelogram-shaped cholesterol monohydrate crystals in knockout mice. Furthermore, three patterns of crystal growth habits were observed: proportional enlargement, spiral dislocation growth, and twin crystal growth, all enlarging solid cholesterol crystals. At day 15 on the lithogenic diet, 75% of knockout mice formed gallstones. However, wild-type mice formed very little mucin gel, liquid, and solid crystals, and gallstones were not observed. We conclude that lack of CCK induces gallbladder hypomotility that prolongs the residence time of excess cholesterol in the gallbladder, leading to rapid crystallization and precipitation of solid cholesterol crystals. Moreover, during the early stage of gallstone formation, there are two pathways of liquid and polymorph anhydrous crystals evolving to monohydrate crystals and three modes for cholesterol crystal growth.

Roles of infection, inflammation, and the immune system in cholesterol gallstone formation

Cholesterol gallstone formation is a complex process mediated by genetic and environmental factors. Until recently, the role of the immune system in the pathogenesis of cholesterol gallstones was not considered a valid topic of research interest. This review collates and interprets an extensive body of basic literature, some of which is not customarily considered to be related to cholelithogenesis, describing the multiple facets of the immune system that appear to be involved in cholesterol cholelithogenesis. A thorough understanding of the immune interactions with biliary lipids and cholecystocytes should modify current views of the pathogenesis of cholesterol gallstones, promote further research on the pathways involved, and lead to novel diagnostic tools, treatments, and preventive measures.

Impact of food on hepatic clearance of patients after endoscopic sphincterotomy

BACKGROUND

The recurrence rate of common bile duct stones (CBDS) is around 3-21% after treatment by endoscopic sphincterotomy (ES). Fatty meal has been shown to improve hepatic clearance in both patients with intact gallbladder and post-cholecystectomy after ES. This study tested the effects of different kinds of food on hepatic clearance by using quantitative cholescintigraphy (QC) in patients after ES.

METHODS

Forty-seven patients after ES with abnormal QC were enrolled in our study. Complete ablation of sphincter function was confirmed by sphincter of Oddi manometry. Fasting QC was done in every patient shortly after normalization of liver function, and then followed with low-fat and fatty-meal QC. Each of the 47 subjects was observed for the effect on hepatic clearance at 3 different levels of treatments (diets and fasting). Additionally, possible factors responsible for recurrent CBDS were investigated by means of logistic regression.

RESULTS

Both fatty and low-fat meals could significantly improve hepatic clearance compared with fasting in most patients after ES. But the response to food types was individualized. All patients tolerated the meals well. There was no significant relationship between the recurrence of CBDS and sex, age, intact gallbladder and presence of juxtapapillary diverticulum, CBD size, and improvement in hepatic clearance (> or = 5%) by food.

CONCLUSION

Both fatty and low-fat meals improved hepatic clearance in most of the patients with CBDS after ES, but the response to meals was individualized. Therefore, there is no need to restrict the amount of fat intake for patients who have undergone ES.

Early changes in postprandial gallbladder emptying in morbidly obese patients undergoing Roux-en-Y gastric bypass: correlation with the occurrence of biliary sludge and gallstones

BACKGROUND

Gallstones have been frequently diagnosed after Roux-en-Y gastric bypass (RYGBP). Gallbladder stasis associated with duodenal exclusion may play a role in their pathogenesis.

METHODS

Gallbladder emptying was studied before and on the 30th and 31st postoperative days (POD) after RYGBP in 20 morbidly obese patients. Gallbladder volume after fasting and every 15 min during a 2-h period following administration of a standard liquid meal was determined by sonography. On the 31st POD, the meal was administered through the gastrostomy in order to promote its transit through the duodenum. Fasting volume (FV), maximum ejection fraction (Max EF), and residual volume (RV) were determined. Biliary sludge and calculi were investigated after 1 and 6 months, respectively.

RESULTS

FV was 39.4 +/- 20.2 ml, 50.1 +/- 22.7 ml, and 47.9 +/- 23.4 ml, respectively, for the preoperative and two postoperative assessments (P = 0.09). RV was 7.6 +/- 8.7 ml, 25.1 +/- 20.0 ml, and 24.6 +/- 20.9 ml; and Max EF was 80.5 +/- 20.9%, 54.3 +/- 21.4%, and 50.5 +/- 29.0%, respectively, for the pre-, postoral, and postgastrostomy infusion measurements. There was only a significant difference between the preoperative value and the two postoperative values (P < 0.001). Biliary sludge was detected in 65% of the patients and 46% of them subsequently developed gallstones.

CONCLUSIONS

Gallbladder emptying became significantly compromised after RYGBP. This impairment was unrelated to duodenal exclusion but it was associated with biliary sludge and stone formation.

Physical chemistry of intestinal absorption of biliary cholesterol in mice

Although many putative sterol transporters influencing cholesterol absorption and physical-chemical factors affecting dietary cholesterol absorption have been extensively investigated, it is still unclear how biliary cholesterol contributes to the regulation of intestinal cholesterol absorption. We studied whether the gallbladder can modulate the microaggregates of cholesterol carriers, which may in turn influence the intestinal absorption of biliary cholesterol. Supersaturated, crystallized, or micellar model biles were delivered via a duodenal catheter to conscious, freely moving C57L mice daily for 2 days. Intestinal uptake and absorption of biliary cholesterol and its fecal excretion, as well as expression levels of intestinal sterol transporters, were analyzed. Cholesterol uptake and absorption by the enterocyte were dramatically reduced in mice treated with crystallized biles compared with supersaturated biles. This correlated with the higher cumulative radioactivity of cholesterol recovered in the feces at 24 hours. Such findings were absent with the added reference compound sitostanol. After removing cholesterol crystals from crystallized biles, micellar biles showed essentially identical effects on intestinal absorption but with lower fecal cholesterol excretion compared with the original samples containing crystals. Expression levels of the jejunal Abcg5 (ATP-binding cassette transporter G5) and Abcg8, but not Npc1l1 (Niemann-Pick C1 like 1), were significantly increased by supersaturated biles compared with crystallized biles.

CONCLUSION

Different physical forms of biliary cholesterol dramatically determine intestinal uptake and absorption of cholesterol. Solid plate-like cholesterol monohydrate crystals in bile are probably not absorbed and are totally excreted in feces from the body. The gallbladder may have a role in regulating cholesterol homeostasis by modulating the physical forms of biliary cholesterol.

Ursodeoxycholic acid in the prevention of gallstone formation after bariatric surgery: a meta-analysis

BACKGROUND

Rapid weight loss increases risk for gallstone formation. Prophylactic cholecystectomy is difficult. Several small trials have shown that ursodeoxycholic acid (UDCA) may prevent gallstone formation after bariatric surgery. The aim of this study is to assess the efficacy and safety of UDCA in the prevention of gallstone formation after bariatric surgery.

METHODS

Electronic databases, including the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, Australasian Medical Index, LILACS, and HERDIN, were searched. Reference lists of trials selected by the above electronic searching were also searched. Authors of the retrieved trials and pharmaceutical companies were also contacted for other trials, published and unpublished. A meta-analysis of all randomized, double-blind, placebo-controlled prospective trials comparing UDCA and placebo was performed.

RESULTS

Five RCTs including 521 patients were assessed. Random effects meta-analysis showed a significant reduction of gallstone formation (RR 0.43, 95% confidence interval 0.22-0.83), with 8.8% of those taking UDCA developing gallstones compared to 27.7% for placebo. Although this meta-analysis is heterogeneous with I(2) of 61.9%, the directions of the effect are all consistently in favor of UDCA (p=0.01). A meta-analysis on the adverse effects could not be performed because the studies did not report them in a way to make the analysis possible.

CONCLUSIONS

UDCA can prevent gallstone formation after bariatric surgery.

Gallstone disease: from genes to evidence-based therapy

The number of gallstone patients is increasing in ageing populations with a high prevalence of metabolic syndrome and obesity. Recently variants of hepatic ATP binding cassette transporters have been identified as genetic susceptibility factors for gallstone disease, pointing to novel means for risk assessment and prevention. Although laparoscopic cholecystectomy is the mainstay of therapy for symptomatic gallbladder stones, the clinical management of gallstone disease is changing rapidly, with an increase in day case surgery and the advent of transluminal endoscopic surgery. Here, we summarize the molecular and genetic mechanisms of gallstone formation as well as the current evidence-based algorithms for diagnosis and therapy of gallbladder and bile duct stones.

Gallstone formation after pancreas and/or kidney transplantation: an analysis of risk factors

Pancreas and kidney transplantation (SPK) is the treatment of choice for patients with type 1 diabetes mellitus and end-stage renal failure. Gallstones are common after SPK transplantation but little is known about the true incidence and etiology of gallstones in this group. We therefore evaluated the incidence of gallstones and the presence of transplant-related risk factors in patients after SPK and kidney transplantation alone (KTA). Data were evaluated of 56 consecutive patients who underwent SPK transplantation and compared the results with those of 91 consecutive nondiabetic patients who underwent KTA transplantation at the Leiden University Medical Center between 1987 and 1994. Of the 58 evaluable KTA patients, 20.7% developed gallstones during 7.7 yr of follow-up and in the SPK group 43.9% of the 41 evaluable patients developed gallstones during 7.1 yr of follow-up. Postoperative weight loss and cyclosporin A-related hepatotoxicity correlated with gallstone formation both in SPK and KTA patients. In addition, the duration of postoperative fasting and autonomic neuropathy correlated with gallstones in SPK patients. It is concluded that both in patients after SPK transplantation and in patients after KTA transplantation, the risk to develop gallstones is significantly increased. Physicians should be aware of the high incidence of gallstones in SPK recipients.

Gallstone disease

Gallstone disease is one of the most prevalent gastrointestinal diseases with a substantial burden to health care systems that is supposed to increase in ageing populations at risk. Aetiology and pathogenesis of cholesterol gallstones still are not well defined, and strategies for prevention and efficient nonsurgical therapies are missing. This review summarizes current concepts on the pathogenesis of cholesterol gallstones with focus on the uptake and secretion of biliary lipids and special emphasis on recent studies into the genetic background.