Gallbladder bile composition in patients with Crohn’s disease

Association between dietary potassium intake and the prevalence of gallstones in American adults: an assessment of data from the national health and nutrition examination survey

BACKGROUND

Gallstones are a common disease of the digestive system, and its complications pose serious risks to human health and impose a significant economic burden on society. Inadequate dietary potassium intake may be associated with the development of gallstones, however, there is a lack of current epidemiological research on this topic.

OBJECTIVE

The purpose of this research was a preliminarily exploration of the relationship between dietary potassium intake and the prevalence of gallstones, providing direction for the next step of quantitativeanalysis on the association between dietary potassium intake and the prevalence of gallstones.

METHODS

Data from the National Health and Nutrition Examination Survey (NHANES) spanning 2017 to 2020 were used for a cross-sectional analysis. The presence of gallstones was assessed based on the NHANES questionnaire data for the corresponding time frame. To investigate the link between dietary potassium consumption and the likelihood of developing gallstones, multiple logistic regression models were used. Subgroup analyses were conducted based on variables such as age, gender, poverty-to-income ratio (PIR), body mass index (BMI), hypertension, diabetes, dietary supplement use, and physical activity. An analysis of linear associations was carried out using smoothing curves.

RESULTS

The study comprised 6,223 participants aged 20 years and older, excluding pregnant individuals. Among these participants, 671 were diagnosed with gallstones. In the final adjusted model, with a 95% confidence interval (CI) of 0.70 to 0.93, it was determined that dietary potassium intake and gallstone incidence were negatively correlated (OR = 0.81, p = 0.003). Individuals in the highest tertile of dietary potassium intake experienced a 31% lower risk of developing gallstones compare to those in the lowest tertile (OR = 0.69, 95% CI: 0.51-0.94, p = 0.017). In Model 1, the prevalence of gallstones exhibited an inverse relationship with dietary potassium intake. This negative association persisted even after stratifying by variables such as age, gender, PIR, BMI, hypertension, diabetes, dietary supplement use, and physical activity. Sensitivity analyses demonstrated the stability of this relationship.

CONCLUSION

Our research revealed that increased dietary potassium intake is associated with a lower prevalence of gallstones. Nevertheless, additional prospective studies are required to confirm a precise dietary potassium intake level and the long-term effects of potassium metabolism on gallstone formation.

Risk Factors for Gallstones in Crohn's Disease: A Systematic Review and Meta-Analysis

BACKGROUND

Crohn's disease (CD) have an increased risk of gallstone disease. We aimed to systematically evaluate the prevalence rate and relevant risk factors of gallstones in CD patients.

METHODS

A comprehensive search of PubMed, Embase, and Web of Science databases from inception to September 10, 2023, identified studies investigating risk factors for gallstone development among CD patients. Gender, age, body mass index, disease duration, disease site, stenosis, prior surgery, hospitalization times, corticosteroids, immunomodulators, and total parenteral nutrition (TPN) were assessed as potential risk factors. Odds ratios (OR) and confidence intervals (CI) were calculated.

RESULT

Among 1184 articles, 11 observational studies (3588 patients) were included. The prevalence of CD patients with gallstones was approximately 14.7%. Factors significantly associated with increased gallstone risk included Age ≥ 40 years old (OR 3.06, 95% CI 2.09- 4.48), disease duration > 15 years (OR 3.01, 95% CI 2.06-4.42), lifetime surgery(OR 2.50, 95% CI 1.99-3.12), disease located in ileocolon (OR 1.38, 95% CI 1.04-1.83) and ileocecal(OR 1.93, 95% CI 1.16-3.21), multiple hospitalizations(OR 4.26, 95% CI 2.43-7.46), corticosteroid treatments(OR 2.65, 95% CI 1.52-4.63), immunomodulator therapy(OR 1.94, 95% CI 1.12-3.38), and TPN use(OR 2.66, 95% CI 1.29-5.51). Sex, stenosis, overweight, or low weight did not significantly increase the risk of gallstone developing.

CONCLUSION

Age, long disease duration, specific disease locations (ileocolon, ileocecal), surgery, number of hospitalizations, corticosteroids, immunomodulator therapy, and TPN were identified as factors that increased the risk of gallstones in CD patients. About 14.7% of CD patients experience gallstones, so raising awareness and implementing prevention are needed.

REGISTRATION

PROSPERO (CRD42023449299).

Untargeted faecal metabolomics for the discovery of biomarkers and treatment targets for inflammatory bowel diseases

The gut microbiome has been recognised as a key component in the pathogenesis of inflammatory bowel diseases (IBD), and the wide range of metabolites produced by gut bacteria are an important mechanism by which the human microbiome interacts with host immunity or host metabolism. High-throughput metabolomic profiling and novel computational approaches now allow for comprehensive assessment of thousands of metabolites in diverse biomaterials, including faecal samples. Several groups of metabolites, including short-chain fatty acids, tryptophan metabolites and bile acids, have been associated with IBD. In this Recent Advances article, we describe the contribution of metabolomics research to the field of IBD, with a focus on faecal metabolomics. We discuss the latest findings on the significance of these metabolites for IBD prognosis and therapeutic interventions and offer insights into the future directions of metabolomics research.

A Clinical and Pathophysiological Overview of Intestinal and Systemic Diseases Associated with Pancreatic Disorders: Causality or Casualty?

The relationship between chronic intestinal disease, including inflammatory bowel disease (IBD) and celiac disease (CelD), and pancreatic disorders has been little investigated. Although an increased risk of acute pancreatitis (AP), exocrine pancreatic insufficiency with or without chronic pancreatitis, and chronic asymptomatic pancreatic hyperenzymemia have been described in these patients, the pathogenetic link remains unclear. It may potentially involve drugs, altered microcirculation, gut permeability/motility with disruption of enteric-mediated hormone secretion, bacterial translocation, and activation of the gut-associated lymphoid tissue related to chronic inflammation. In addition, the risk of pancreatic cancer seems to be increased in both IBD and CelD patients with unknown pathogenesis. Finally, other systemic conditions (e.g., IgG4-related disease, sarcoidosis, vasculitides) might affect pancreatic gland and the intestinal tract with various clinical manifestations. This review includes the current understandings of this enigmatic association, reporting a clinical and pathophysiological overview about this topic.

Discovery of the gut microbial enzyme responsible for bilirubin reduction to urobilinogen

The degradation of heme and the interplay of its catabolic derivative, bilirubin, between humans and their gut microbiota is an essential facet of human health. However, the hypothesized bacterial enzyme that reduces bilirubin to urobilinogen, a key step that produces the excretable waste products of this pathway, has remained unidentified. In this study, we used a combination of biochemical analyses and comparative genomics to identify a novel enzyme, BilR, that can reduce bilirubin to urobilinogen. We delineated the BilR sequences from other members of the Old Yellow Enzyme family through the identification of key residues in the active site that are critical for bilirubin reduction and found that BilR is predominantly encoded by Firmicutes in the gut microbiome. Our analysis of human gut metagenomes showed that BilR is a common feature of a healthy adult human microbiome but has a decreased prevalence in neonates and IBD patients. This discovery sheds new light on the role of the gut microbiome in bilirubin metabolism and highlights the significance of the gut-liver axis in maintaining bilirubin homeostasis.

Functional, Diagnostic and Therapeutic Aspects of Bile

Bile is a unique body fluid synthesized in our liver. Enterohepatic circulation preserves bile in our body through its efficient synthesis, transport, absorption, and reuptake. Bile is the main excretory route for bile salts, bilirubin, and potentially harmful exogenous lipophilic substances. The primary way of eliminating cholesterol is bile. Although bile has many organic and inorganic contents, bile acid is the most physiologically active component. Bile acids have a multitude of critical physiologic functions in our body. These include emulsification of dietary fat, absorption of fat and fat-soluble vitamins, maintaining glucose, lipid, and energy homeostasis, sustenance of intestinal epithelial integrity and epithelial cell proliferation, reducing inflammation in the intestine, and prevention of enteric infection due to its antimicrobial properties. But bile acids can be harmful in certain altered conditions like cholecystectomy, terminal ileal disease or resection, cholestasis, duodenogastric bile reflux, duodenogastroesophageal bile reflux, and bile acid diarrhea. Bile acids can have malignant potentials as well. There are also important diagnostic and therapeutic roles of bile acid and bile acid modulation.

Pancreatic Disorders in Patients with Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) can involve multiple organ systems, and pancreatic manifestations of IBD are not uncommon. The incidence of several pancreatic diseases is more frequent in patients with Crohn's disease and ulcerative colitis than in the general population. Pancreatic manifestations in IBD include a heterogeneous group of disorders and abnormalities ranging from mild, self-limited disorders to severe diseases. Asymptomatic elevation of amylase and/or lipase is common. The risk of acute pancreatitis in patients with IBD is increased due to the higher incidence of cholelithiasis and drug-induced pancreatitis in this population. Patients with IBD commonly have altered pancreatic histology and chronic pancreatic exocrine dysfunction. Diagnosing acute pancreatitis in patients with IBD is challenging. In this review, we discuss the manifestations and possible causes of pancreatic abnormalities in patients with IBD.

Association of metabolites with obesity based on two gene variants, MC4R rs17782313 and BDNF rs6265

Previous genome-wide association analyses for obesity related genes demonstrated the association of BDNF gene variant rs6265 and MC4R gene variant rs17782313 with body mass index (BMI). However, the associated metabolite pathways are still behind the curtain. The aim of the current study is to investigate the associations of metabolic changes in obesity with MC4R gene variant rs17782313 and BDNF variant rs6265. Gas chromatography-mass spectrometry based untargeted metabolomics approach was used and 42 identified serum metabolites were selected for statistical analyses. Significant association of seven metabolites with MC4R gene variant rs17782313 based on obesity and thirty metabolites with obesity dependent BDNF variant rs6265 using additive model (adjusted p < 0.05) was observed. This study highlights the importance of alteration of fatty acid biosynthesis, probably due to high consumption of fats may cause to develop obesity. But obesity is a complex disorder and the full clarification of this complex machinery is still distant. To understand the obesity in a better way, more studies are required to identify remaining metabolites and also mechanism of these metabolic entities.

Metabolomics as a Promising Resource Identifying Potential Biomarkers for Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a relapsing chronic disorder of the gastrointestinal tract characterized by disruption of epithelial barrier function and excessive immune response to gut microbiota. The lack of biomarkers providing early diagnosis or defining the status of the pathology difficulties an accurate assessment of the disease. Given the different metabolomic profiles observed in IBD patients, metabolomics may reveal prime candidates to be studied, which may help in understanding the pathology and identifying novel therapeutic targets. In this review, we summarize the most current advances describing the promising metabolites such as lipids or amino acids found through untargeted metabolomics from serum, faecal, urine and biopsy samples.

Population-based case-control study revealed metabolomic biomarkers of suboptimal health status in Chinese population-potential utility for innovative approach by predictive, preventive, and personalized medicine

BACKGROUND

Suboptimal health status (SHS) is a subclinical stage of chronic diseases, and the identification of SHS provides an opportunity for the predictive, preventive, and personalized medicine (PPPM) of chronic diseases. Previous studies have reported the associations between metabolic signatures and early signs of chronic diseases.

METHODS

This study aimed to detect the metabolic biomarkers for the identification of SHS in a case-control study. SHS questionnaire-25 (SHSQ-25) was used in a population-based health survey to measure the SHS levels of participants. The liquid chromatography-mass spectrometry-based untargeted metabolomics analysis was conducted on plasma samples collected from 50 SHS participants and 50 age- and sex-matched healthy controls.

RESULTS

After adjusting for the confounders, 24 significantly differential metabolites, such as sphingomyelin, sphingosine, sphinganine, progesterone, pregnanolone, and bilirubin, were identified as the candidate biomarkers for SHS. Pathway analysis revealed that sphingolipid metabolism, taurine metabolism, and steroid hormone biosynthesis are the disturbed metabolic pathways related to SHS. A combination of four metabolic biomarkers (sphingosine, pregnanolone, taurolithocholate sulfate, cervonyl carnitine) can distinguish SHS individuals from the controls with a sensitivity of 94.0%, a specificity of 90.0%, and an area under the receiver operating characteristic curve of 0.977.

CONCLUSION

Plasma metabolites are valuable biomarkers for SHS identification, and meanwhile, SHSQ-25 can be used as an alternative health screening tool in the population-based health survey. SHS-related metabolic disturbances could be detected at the early onset of SHS, and SHS-related metabolites could create a window opportunity for PPPM of chronic diseases.

Other Surgeries in Patients with Inflammatory Bowel Disease

Patients with inflammatory bowel disease (IBD) will often require abdominal surgical intervention for indications not directly related to their IBD. Because these patients often have a history of multiple previous abdominal operations and/or ostomies, they are at increased risk for incisional and parastomal hernias. They may also have develop symptomatic cholelithiasis, chronic pain, or desmoid disease. All of these potentially surgical issues may require special consideration in the IBD population.

Murine epithelial sodium (Na+) channel regulation by biliary factors

The epithelial sodium channel (ENaC) mediates Na+ transport in several epithelia, including the aldosterone-sensitive distal nephron, distal colon, and biliary epithelium. Numerous factors regulate ENaC activity, including extracellular ligands, post-translational modifications, and membrane-resident lipids. However, ENaC regulation by bile acids and conjugated bilirubin, metabolites that are abundant in the biliary tree and intestinal tract and are sometimes elevated in the urine of individuals with advanced liver disease, remains poorly understood. Here, using a Xenopus oocyte-based system to express and functionally study ENaC, we found that, depending on the bile acid used, bile acids both activate and inhibit mouse ENaC. Whether bile acids were activating or inhibiting was contingent on the position and orientation of specific bile acid moieties. For example, a hydroxyl group at the 12-position and facing the hydrophilic side (12α-OH) was activating. Taurine-conjugated bile acids, which have reduced membrane permeability, affected ENaC activity more strongly than did their more membrane-permeant unconjugated counterparts, suggesting that bile acids regulate ENaC extracellularly. Bile acid-dependent activation was enhanced by amino acid substitutions in ENaC that depress open probability and was precluded by proteolytic cleavage that increases open probability, consistent with an effect of bile acids on ENaC open probability. Bile acids also regulated ENaC in a cortical collecting duct cell line, mirroring the results in Xenopus oocytes. We also show that bilirubin conjugates activate ENaC. These results indicate that ENaC responds to compounds abundant in bile and that their ability to regulate this channel depends on the presence of specific functional groups.

Evidence of Disturbed Gut Microbial Metabolic Activity in Pediatric Crohn’s Disease

Background

Dysbiosis, that is, disturbed gut microbial balance, is well documented in Crohn’s disease (CD). We aimed at studying CD-linked dysbiosis in children by analyzing fecal microbe-associated characteristics, previously not reported in children.

Methods

This observational study included 28 children with active CD and healthy controls. We assessed the following three indicators of gut microbiota metabolism in the feces: the presence of tryptic activity, the conversion of cholesterol to coprostanol, and the conversion of bilirubin to urobilinogen.

Results

The fecal tryptic activity was significantly higher in children with active CD compared to the control group (P &lt; 0.01). The fecal coprostanol of the CD children was close to zero and differed significantly from the controls (P &lt; 0.001). Furthermore, the children with CD had very low fecal urobilinogen, differing significantly from the control group (P &lt; 0.001).

Conclusions

The significant differences in levels of fecal bacterial metabolites in patients with active CD compared to healthy controls reflect major perturbation of gut microbial functions and have not previously been reported in children. This fits well with the prevailing concept of a dysbiotic gut microbiota in CD and may have important clinical implications by bringing the dysbiosis back into balance.

Cholecystectomy Risk in Crohn's Disease Patients After Ileal Resection: a Long-term Nationwide Cohort Study

BACKGROUND

The risk of gallstone disease necessitating cholecystectomy after ileal resection (IR) in Crohn's disease (CD) patients is not well established. We studied the incidence, cumulative and relative risk of cholecystectomy after IR in CD patients, and associated risk factors.

METHODS

CD patients with a first IR between 1991 and 2015 were identified in PALGA, a nationwide pathology database in the Netherlands. Details on subsequent cholecystectomy and IR were recorded. Yearly cholecystectomy rates from the general Dutch population were used as a reference.

RESULTS

A cohort of 8302 (3466 (41.7%) males) CD patients after IR was identified. During the 11.9 (IQR 6.3-18.0) years median follow-up, the post-IR incidence rate of cholecystectomy was 5.2 (95% CI 3.5-6.4)/1000 persons/year. The cumulative incidence was 0.5% at 1 year, 2.4% at 5 years, 4.6% at 10 years, and 10.3% after 20 years. In multivariable analyses, female sex (HR 1.9, CI 1.5-2.3), a later calendar year of first IR (HR_{/5-year increase}, HR 1.27, CI 1.18-1.35), and ileal re-resection (time-dependent HR 1.37, CI 1.06-1.77) were associated with cholecystectomy. In the last decade, cholecystectomy rates increased and were higher in our postoperative CD population than in the general population (relative incidence ratio 3.13 (CI 2.29-4.28; p < 0.0001) in 2015).

CONCLUSIONS

Although higher in females, increasing in recent years, and higher than in the general population, the overall risk of cholecystectomy in CD patients following IR is low and routine prophylactic measures seem unwarranted.

Risk Factors for Cholelithiasis

Gallstone disease is one of the most common public health problems in the United States. Approximately 10%-20% of the national adult populations currently carry gallstones, and gallstone prevalence is rising. In addition, nearly 750,000 cholecystectomies are performed annually in the United States; direct and indirect costs of gallbladder surgery are estimated to be $6.5 billion. Cholelithiasis is also strongly associated with gallbladder, pancreatic, and colorectal cancer occurrence. Moreover, the National Institutes of Health estimates that almost 3,000 deaths (0.12% of all deaths) per year are attributed to complications of cholelithiasis and gallbladder disease. Although extensive research has tried to identify risk factors for cholelithiasis, several studies indicate that definitive findings still remain elusive. In this review, predisposing factors for cholelithiasis are identified, the pathophysiology of gallstone disease is described, and nonsurgical preventive options are discussed. Understanding the risk factors for cholelithiasis may not only be useful in assisting nurses to provide resources and education for patients who are diagnosed with gallstones, but also in developing novel preventive measures for the disease.

Reduced total serum bilirubin levels are associated with ulcerative colitis

Chronic inflammation associated with inflammatory bowel disease (IBD) results in increased oxidative stress that damages the colonic microenvironment. Low levels of serum bilirubin, an endogenous antioxidant, have been associated with increased risk for Crohn's disease (CD). Therefore, the aim of this study was to examine whether total serum bilirubin levels are associated with ulcerative colitis (UC). We identified a retrospective case-control population (n = 6,649) from a single tertiary care center, Penn State Hershey Medical Center (PSU) and a validation cohort (n = 1,996) from Virginia Commonwealth University Medical Center (VCU). Cases were age- and sex-matched to controls (PSU: CD n = 254, UC n = 187; VCU: CD n = 233, UC n = 124). Total serum bilirubin levels were obtained from de-identified medical records and segregated into quartiles. Logistic regression analysis was performed on each quartile of total serum bilirubin compared to the last quartile (highest bilirubin levels) to determine the association of total serum bilirubin with UC. Similar to CD patients, UC patients demonstrated reduced levels of total serum bilirubin compared to controls at PSU and VCU. The lowest quartile of total serum bilirubin was independently associated with UC for the PSU (OR: 1.98 [95% CI: 1.09-3.63]) and VCU cohorts (OR: 6.07 [95% CI: 3.01-12.75]). Lower levels of the antioxidant bilirubin may reduce the capability of UC patients to remove reactive oxygen species leading to an increase in intestinal injury. Therapeutics that reduce oxidative stress may be beneficial for these patients.

Probing the Association of Pancreatitis in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) has been increasingly diagnosed in children and adults. Similarly, acute and chronic pancreatitis are increasingly prevalent conditions with potentially devastating consequences. There is a growing body of literature linking these 2 conditions. The purpose of this review is to provide a comprehensive outline of the association between IBD and pancreatitis and to explore their putative pathophysiology. Based on the collective reports, 2 outstanding reasons for pancreatitis in patients with IBD are medications and IBD complications.

Inflammatory Bowel Disease and Pancreatitis: A Review

BACKGROUND AND AIMS

Pancreatic abnormalities are common in inflammatory bowel disease (IBD) patients and represent a heterogeneous group of conditions that include acute pancreatitis, chronic pancreatitis, autoimmune pancreatitis and asymptomatic abnormalities. We sought to review the available evidence concerning the aetiology, clinical presentation, diagnosis and treatment of pancreatic conditions in IBD patients.

METHODS

A PubMed/Medline query was conducted addressing pancreatic disorders in IBD. Reference lists from studies selected were manually searched to identify further relevant reports. Relevant manuscripts about pancreatic disorders in patients with IBD were selected and reviewed.

RESULTS

Thiopurines and gallstones are the most frequent causes of acute pancreatitis in IBD patients. Thiopurine-induced acute pancreatitis is usually uncomplicated and self-limited. Some evidence suggests that chronic pancreatitis may be more common in IBD. Most cases are idiopathic, affecting young males and patients with ulcerative colitis. Autoimmune pancreatitis is a relatively newly recognized disease and is increasingly diagnosed in IBD, particularly for type 2 autoimmune pancreatitis in ulcerative colitis patients. Asymptomatic exocrine insufficiency, pancreatic duct abnormalities and hyperamylasaemia have been identified in up to 18% of IBD patients, although their clinical significance and relationship with IBD remain undefined.

CONCLUSIONS

The wide spectrum of pancreatic manifestations in IBD is growing and may represent a challenge to the clinician. A collaborative approach with a pancreas specialist may be the most productive route to determine aetiology, guide additional diagnostic workup, illuminate the aetiology and define the treatment and follow-up of these patients.

Systematic review: The epidemiology of the hepatobiliary manifestations in patients with inflammatory bowel disease

BACKGROUND

Extraintestinal manifestations are frequent in inflammatory bowel diseases (IBD). Most studies published so far focused on viral hepatitis and liver toxicity of IBD-related drugs.

AIM

To conduct a systematic review of hepatobiliary manifestations associated with IBD. We excluded viral hepatitis and liver toxicity of IBD-related drugs.

METHODS

Studies were identified through the electronic database of MEDLINE, EMBASE and the annual meetings of Digestive Disease Week, the American College of Gastroenterology, the United European Gastroenterology Week and the European Crohn's and Colitis Organization.

RESULTS

One hundred and forty six articles were included in this systematic review. Cholelithiasis is more frequent in Crohn's disease (CD) than in general population. Prevalence of cholelithiasis in CD ranged from 11% to 34%, whereas it ranges from 5.5% to 15% in non-IBD patients. PSC is more frequent in UC than in CD. Prevalence of PSC ranges from 0.76% to 5.4% in UC and from 1.2% to 3.4% in CD. There is a male predominance when PSC is associated with UC, with a male/female ratio ranging from 65/35 to 70/30. No conclusion can be made on a possible increased risk of gall-bladder carcinoma. Mean prevalence of fatty liver is 23% (range, 1.5-55%). Hepatic amyloidosis occurs in less than 1% of IBD. Liver abscess is encountered mainly in CD. Portal vein thrombosis occurs in 39% to 45% of IBD patients undergoing proctocolectomy.

CONCLUSIONS

Hepatobiliary manifestations associated with inflammatory bowel diseases are frequent and probably underdiagnosed.

Bowel functions, fecal unconjugated primary and secondary bile acids, and colonic transit in patients with irritable bowel syndrome

BACKGROUND & AIMS

There is an unclear relationship among bowel symptoms, excretion of unconjugated fecal bile acid (UBA), and colonic transit in irritable bowel syndrome (IBS). We measured total and main individual UBA in fecal samples of patients with IBS and assessed relationships among stool frequency or consistency, fecal UBA (total and individual), and colonic transit.

METHODS

In this study 30 healthy volunteers (controls), 31 subjects with IBS with diarrhea (IBS-D), and 30 with IBS with constipation (IBS-C) were placed on 4-day diets containing 100 g fat; we measured stool characteristics, total fecal UBA and fat levels, and overall colonic transit. We assessed univariate associations of total and individual levels of fecal UBA with phenotype (controls, IBS-D, IBS-C) by using the Kruskal-Wallis test; associations between end points were assessed by using Spearman correlations. With response surface regression models, we assessed relationships between stool, colonic transit, and fecal total and secretory UBA.

RESULTS

There was a significant association between total fecal UBA and phenotype (P = .029); the association was greater for IBS-D than IBS-C, compared with controls. Fecal levels of primary UBAs (cholic and chenodeoxycholic acids) were higher in subjects with IBS-D, compared with controls (both P < .01). Levels of fecal secretory UBAs (chenodeoxycholic acid, P = .019; deoxycholic acid, P = .025) were lower in subjects with IBS-C compared with controls, whereas levels of the nonsecretory UBA, lithocholic acid, were higher (P = .020). There were significant univariate associations between stool number and form and total fecal UBA (including percentages of lithocholic acid, chenodeoxycholic acid and cholic acid), fecal fat, and colonic transit at 24 and 48 hours after eating. In the regression models, the relative contribution of colonic transit was consistently greater and largely independent of the contribution of bile acids.

CONCLUSIONS

Measurements of individual UBAs identify changes associated with stool characteristics in patients with IBS; these effects are independent of the effects of colonic transit.

Liver abnormalities in bowel diseases

Liver abnormalities are often seen in bowel diseases. Whether these represent aspects of two separate diseases, or if one is causing the other, is not always easy to decide. Extraintestinal manifestations of inflammatory bowel disease (IBD) or coeliac disease are frequently observed. Of these extraintestinal manifestations, hepatic disorders are among the most common. Primary sclerosing cholangitis (PSC) and primary biliary cirrhosis are the most frequent hepatic disorders in IBD and coeliac disease, respectively. Genetic studies have lately elucidated the associations between IBD and PSC, but there is still a long way until we have complete understanding of the molecular aetiology and pathophysiology of these conditions. There is no curative treatment available for PSC, besides liver transplantation. Steatosis and cholelithiasis are also common in IBD, as are signs of hepatic injury due to IBD treatment. Less common liver abnormalities include liver abscesses, hepatic thromboembolic events, granulomatous liver disease and hepatic amyloidosis.

Altered enterohepatic circulation of bile acids in Crohn's disease and their clinical significance: a new perspective

The role of bile acids (BA) extends far beyond lipid digestion and cholesterol metabolism. The transcriptional regulation of multiple genes within the liver and intestine are under their influence. BA exert these effects through binding and activating receptors in much the same way as endocrine hormones. The farnesoid X receptor (FXR) is the intracellular transcription factor for BA; TGR5 is the cell-surface receptor. The main target genes of FXR are those involved in BA and cholesterol metabolism. Yet more recently, FXR has also been shown to influence and promote certain protective pathways within the liver. These pathways are being harnessed by semisynthetic BAs in Phase II and III clinical trials. FXR activation within the intestine is also associated with similar protective pathways. This article examines the consequences of altered FXR activation in the context of BA malabsorption in Crohn's disease and the potential benefits of FXR agonists in Crohn's disease.

Bile salts induce long polar fimbriae expression favouring Crohn's disease-associated adherent-invasive Escherichia coli interaction with Peyer's patches

Ileal lesions of patients with Crohn's disease are colonized by adherent-invasive Escherichia coli (AIEC). The earliest lesions of recurrent Crohn's disease are erosions of Peyer's patches (PP). We recently reported the presence of a functional lpf operon in AIEC, encoding long polar fimbriae (LPF), that allows AIEC bacteria to interact with PP and to translocate across M cells. The aim of this study was to analyse the effect of gastrointestinal conditions on LPF expression in AIEC strains. The LF82 bacterial growth in an acid pH medium or at high osmolarity medium had no effect on lpf transcription level, in contrast to bacterial growth in the presence of bile salts, which promoted activation of lpf transcription. When cultured in the presence of bile salt, LF82 wild-type bacteria, but not the isogenic mutant deleted for lpfA, exhibited a higher level of interaction with PP and a higher level of translocation through M cell monolayers. The FhlA transcriptional factor was found to be a key bacterial regulator at the origin of LPF expression in the presence of bile salts.

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.

Crohn's disease as an immunodeficiency

The pathogenesis of Crohn's disease (CD) has widely been regarded as the consequence of a dysregulated T-cell-mediated response to intestinal microbes, and the majority of the worldwide research effort has focused on characterizing and treating the chronic inflammatory phase of the disease. However, recent molecular biological and clinical investigations indicate that CD is actually a primary immunodeficiency. At first counter-intuitive, the apparent paradox of a pathogenic innate immune defect can be linked mechanistically to the granulomatous chronic inflammation characteristic of the disease. Genome-wide association studies have corroborated the involvement of innate immune dysfunction in the pathogenesis of CD, but less than 20% of the heritable risk is accounted for. By contrast, in vitro and in vivo stimulation of the immune system has highlighted novel areas of interest that may lead to the development of targeted therapeutic and diagnostic tools.

Bile acids: short and long term effects in the intestine

Bile acids have secretory, motility and antimicrobial effects in the intestine. In patients with bile acid malabsorption the amount of primary bile acids in the colon is increased compared to healthy controls. Deoxycholic acid is affecting the intestinal smooth muscle activity. Chenodeoxycholic acid has the highest potency to affect intestinal secretion. Litocholic acid has little effect in the lumen of intestine compared to both deoxycholic acid and chenodeoxycholic acid. There is no firm evidence that clinically relevant concentrations of bile acids induce colon cancer. Alterations in bile acid metabolism may be involved in the pathophysiology of constipation.

Pancreatitis in inflammatory bowel diseases

Crohn's disease and ulcerative colitis, together popularly known as inflammatory bowel disease (IBD), are characterized by a number of extraintestinal manifestations. Although infrequent, acute pancreatitis, and less often chronic pancreatitis, may occur as a result of the disease itself or secondary to the medications used in the treatment. The increased incidence of acute pancreatitis in Crohn's disease can be explained based on the high predisposition to cholesterol as well as pigment stones as a result of ileal disease, anatomic abnormalities of the duodenum, immunologic disturbances associated with IBD, and, above all, to the side effects of many medications used in the treatment. Sulfasalazine, 5-aminosalicylic acid, azathioprine, and 6-mercaptopurine are well known to cause acute pancreatitis as a result of a possible idiosyncratic mechanism. Crohn's disease and ulcerative colitis share many clinical manifestations and treatment modalities. Nonspecific elevations of serum pancreatic enzymes in IBD make it difficult to avoid over diagnosis of acute pancreatitis, particularly in patients with Crohn's disease who suffer from abdominal pain often. The IBD-pancreas association is further reflected in many reports of exocrine as well as endocrine pancreatic insufficiency.

Spontaneous gallbladder pathology in baboons

BACKGROUND

Gallbladder pathology (GBP) is a relatively uncommon, naturally occurring morbidity in both baboons and humans.

METHODS

A retrospective analysis was performed on 7776 necropsy reports over a 20 year period to determine the prevalence of baboon GBP.

RESULTS

Ninety-seven cases of GBP were identified, yielding a 20 year population prevalence of 1.25%. GBP is more common in adult female baboons, occurring with a female to male ratio of nearly 2:1. Among gallbladder pathologies, cholecystitis (35.1%) and cholelithiasis (29.9%) were the most prevalent abnormalities, followed by hyperplasia (16.5%), edema (15.5%), amyloidosis (5.2%), fibrosis (4.1%), necrosis (4.1%), and hemorrhage (1.0%).

CONCLUSION

Many epidemiologic similarities exist between GBP in baboons and humans suggesting that the baboon may serve as a reliable animal model system for investigating GBP in humans.

Metabolomics reveals metabolic biomarkers of Crohn's disease

The causes and etiology of Crohn's disease (CD) are currently unknown although both host genetics and environmental factors play a role. Here we used non-targeted metabolic profiling to determine the contribution of metabolites produced by the gut microbiota towards disease status of the host. Ion Cyclotron Resonance Fourier Transform Mass Spectrometry (ICR-FT/MS) was used to discern the masses of thousands of metabolites in fecal samples collected from 17 identical twin pairs, including healthy individuals and those with CD. Pathways with differentiating metabolites included those involved in the metabolism and or synthesis of amino acids, fatty acids, bile acids and arachidonic acid. Several metabolites were positively or negatively correlated to the disease phenotype and to specific microbes previously characterized in the same samples. Our data reveal novel differentiating metabolites for CD that may provide diagnostic biomarkers and/or monitoring tools as well as insight into potential targets for disease therapy and prevention.

Serum bile acid profiling reflects enterohepatic detoxification state and intestinal barrier function in inflammatory bowel disease

AIM: To determine free and conjugated serum bile acid (BA) levels in inflammatory bowel disease (IBD) subgroups with defined clinical manifestations.

METHODS: Comprehensive serum BA profiling was performed in 358 IBD patients and 310 healthy controls by liquid chromatography coupled to electrospray ionization tandem mass spectrometry.

RESULTS: Serum levels of hyodeoxycholic acid, the CYP3A4-mediated detoxification product of the secondary BA lithocholic acid (LCA), was increased significantly in Crohn’s disease (CD) and ulcerative colitis (UC), while most other serum BA species were decreased significantly. Total BA, total BA conjugate, and total BA glycoconjugate levels were decreased only in CD, whereas total unconjugated BA levels were decreased only in UC. In UC patients with hepatobiliary manifestations, the conjugated primary BAs glycocholic acid, taurocholic acid, and glycochenodeoxycholic acid were as significantly increased as the secondary BAs LCA, ursodeoxycholic acid, and tauroursodeoxycholic acid compared to UC patients without hepatobiliary manifestations. Finally, we found that in ileocecal resected CD patients, the unconjugated primary BAs, cholic acid and chenodeoxycholic acid, were increased significantly compared to controls and patients without surgical interventions.

CONCLUSION: Serum BA profiling in IBD patients that indicates impaired intestinal barrier function and increased detoxification is suitable for advanced diagnostic characterization and differentiation of IBD subgroups with defined clinical manifestations.

Lithogenesis and bile metabolism

Gallstone disease exacts a considerable financial and social burden worldwide leading to frequent physician visits and hospitalizations. Based on their composition, gallstones are categorized as cholesterol, black pigment, and brown pigment, with each category having a unique structural, epidemiologic, and risk factor profile. Cholesterol crystal formation requires the presence of one or more of the following: (a) cholesterol supersaturation, (b) accelerated nucleation, or (c) gallbladder hypomotility/bile stasis. Some risk factors for cholesterol stones include age, gender, genetics, obesity, rapid weight loss, and ileal disease. Generally, pigment stones are formed by the precipitation of bilirubin in bile, with black stones associated with chronic hemolytic states, cirrhosis, Gilbert syndrome, or cystic fibrosis, and brown stones associated with chronic bacterial or parasitic infections.

(1)H and (31)P NMR studies indicate reduced bile constituents in patients with biliary obstruction and infection

Patients with extrahepatic biliary obstruction present with impairment of the normal bile flow, with jaundice and cholangitis as common complications. (1)H and (31)P NMR quantitative analysis of bile specimens from patients with extrahepatic biliary obstruction (n = 80) (with/without jaundice and cholangitis separately and together) was carried out for the chief biliary constituents to determine the relationship between biliary constituents and jaundice (serum bilirubin concentration >or=1.0 mg/dL) and cholangitis (total leucocyte count >11,000 cells/mm(3) and/or fever >38.5 degrees C with/without bile culture positivity). Compared with controls (patients without jaundice and cholangitis), median indices of the chief biliary constituents (total bile acids, cholesterol, phosphatidylcholine and inorganic phosphate) were significantly suppressed in patients with cholangitis and/or jaundice. Quantities of total bile acids, cholesterol and phosphatidylcholine correlated negatively with the quantity of bilirubin and with cholangitis, i.e. total leucocyte count. Suppression of biliary constituents correlated significantly with the severity of jaundice and cholangitis. The decrease in biliary constituents in the presence of jaundice and cholangitis is possibly the result of downregulation of the function of transporters located at the canalicular side of hepatocytes, leading to their suppressed indices in bile. This information may have implications in the examination of bile for clinical studies.

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.