Bile Metabolism and Lithogenesis

Bile from the hemojuvelin-deficient mouse model of iron excess is enriched in iron and ferritin

Iron is an essential nutrient but is toxic in excess. Iron deficiency is the most prevalent nutritional deficiency and typically linked to inadequate intake. Iron excess is also common and usually due to genetic defects that perturb expression of hepcidin, a hormone that inhibits dietary iron absorption. Our understanding of iron absorption far exceeds that of iron excretion, which is believed to contribute minimally to iron homeostasis. Prior to the discovery of hepcidin, multiple studies showed that excess iron undergoes biliary excretion. We recently reported that wild-type mice raised on an iron-rich diet have increased bile levels of iron and ferritin, a multi-subunit iron storage protein. Given that genetic defects leading to excessive iron absorption are much more common causes of iron excess than dietary loading, we set out to determine if an inherited form of iron excess known as hereditary hemochromatosis also results in bile iron loading. We employed mice deficient in hemojuvelin, a protein essential for hepcidin expression. Mutant mice developed bile iron and ferritin excess. While lysosomal exocytosis has been implicated in ferritin export into bile, knockdown of Tfeb, a regulator of lysosomal biogenesis and function, did not impact bile iron or ferritin levels. Bile proteomes differed between female and male mice for wild-type and hemojuvelin-deficient mice, suggesting sex and iron excess impact bile protein content. Overall, our findings support the notion that excess iron undergoes biliary excretion in genetically determined iron excess.

Alterations in the Intestinal Microbiome and Metabolic Profile of British Shorthair Kittens Fed with Milk Replacer

With the rising popularity of pet cats as companion animals, the survival of newborn kittens is often threatened by factors such as inadequate nursing, maternal behavior and blood incompatibility. These challenges require the use of milk replacers for nurturing. To investigate the effects that feeding kittens with an experimental milk replacer (EMR) have on growth and development, intestinal microbiota, immune response and nutrient metabolism, 12 British shorthair kittens were randomly divided into two groups after nursing for the first week of life. Kittens were fed queen's milk or EMR, whereby kittens fed queen's milk served as the control (CON) group. The findings revealed that the CON group exhibited superoxide dismutase (SOD) activity and total antioxidant capacity (T-AOC) (p < 0.01) on day 7. However, the EMR group had better growth performance during the later stage of the experiment (p < 0.05); the immunocompetence and antioxidant capacity of the EMR group were not significantly different from those of the CON group in the middle and late stages of the experiment, and the mean values of all the indexes were slightly better than those of the control group. Sequencing of the 16S rRNA gene in microbiota demonstrated that EMR increased the colonization of bacterial genera, including Lachnospiraceae, Enterococcus, Rothia and Ligilactobacillus. Compared to the CON group, acetate acid (p < 0.05), propionate acid (p < 0.01) and total SCFAs (p < 0.01) in the EMR group were significantly increased. Moreover, the intake of the EMR resulted in the production of distinct metabolites implicated in the metabolism of lipids and amino acids, among other nutrients, thus invigorating the associated metabolic pathways. These results elucidate the impact of administering a milk replacer on gastrointestinal health and nutrient assimilation in kittens. The study provides insights into the use of milk powder alternatives and sets the stage for future research on the formulation and effectiveness of kitten milk replacers.

Association of milk consumption with the incidence of cholelithiasis disease in the US adult population

BACKGROUND

Cholelithiasis is a common digestive system disease that imposes major burden on patients and society. Investigating the relationship between dietary factors and cholelithiasis risk can provide a basis for disease prevention. Previous studies on milk intake and cholelithiasis incidence have been limited.Therefore, the aim of our study was to assess the association between milk consumption and the incidence of cholelithiasis in males and females.

METHODS

We selected 14,722 adults (≥ 18 years old) from National Center for Health Statistics (NHANSE) 2017-2020, and collected general characteristics of patients in the database, such as age, gender, race and body mass index (BMI), as well as dietary information (milk consumption). The occurrence of cholelithiasis was used as the outcome event, and the group was divided into cholelithiasis and non-cholelithiasis groups according to the outcome event. We used logistic regression models in generalized linear model (GLM) functions, controlling for demographic, lifestyle, and dietary factors, to estimate the association between milk intake and the incidence of cholelithiasis in males and females.

RESULTS

A total of 14,722 adults were included. In the present study, the overall weighted prevalence of cholelithiasis was 10.96%, with 15.18% and 6.48% prevalence in females and males, respectively. Compared to infrequent milk intake, frequent milk intake (once a week or more) in females was associated with reduced cholelithiasis risk (OR 0.74, 95% CI 0.61-0.90). Daily milk intake in males was also related to lower cholelithiasis risk (OR 0.69-0.82). As adjusted variables increased in the models, predictive performance was improved (AUC 0.711 in females, 0.730 in males).

CONCLUSIONS

Appropriate milk intake may correlate with decreased cholelithiasis risk. Our study provides a basis for dietary interventions against gallstones, but prospective studies are needed to verify the results.

Factores asociados con colelitiasis en un hospital de Boyacá

Objetivo: determinar los factores de riesgo asociados con el desarrollo de colelitiasis en pacientes atendidos en un hospital de mediana complejidad de 2017 a 2019. Material y métodos: estudio de casos y controles; los casos correspondieron a 56 pacientes con diagnóstico de colelitiasis y los controles a 112 con enfermedades diferentes a colelitiasis atendidos de 2017 a 2019 en el Hospital Regional de Sogamoso, Colombia, por el servicio de cirugía general. Resultados: se hallaron como posibles factores de riesgo para colelitiasis obesidad [OR: 22,35 IC 95% 4,7;92,85], residencia urbana [OR 5,71 IC 95% 1,57;15,18], hipertrigliceridemia [OR 4,52 IC 95% 2,15;21,32] y anticonceptivos orales [OR 2,05 IC 95% 1,07;9,56] Conclusiones: los factores que se asociaron con colelitiasis fueron en orden de importancia obesidad, residencia urbana, hipertrigliceridemia y anticonceptivos orales. El alcohol en el análisis univariado se comportó como un factor protector, sin embargo al realizar la regresión logística binaria, se observó que no tenía asociación con esta entidad patológica.

Feasibility of discrimination of gall bladder (GB) stone and GB polyp using voltage-applied SERS measurement of bile juice samples in conjunction with two-trace two-dimensional (2T2D) correlation analysis

Voltage-applied SERS measurement of bile juice in conjunction with two-trace two-dimensional (2T2D) correlation analysis was demonstrated as a potential tool to enhance discrimination of gall bladder (GB) stone and GB polyp. When SERS spectra of the aqueous phases extracted from raw bile juice samples were measured with applying external voltage from -300 to +300 mV (100 mV intervals), subsequent spectral variations of the adsorbed components (bilirubin-containing compounds) on the SERS substrate were minute, and discrimination of the two GB diseases in a principal component score domain was difficult. Therefore, 2T2D correlation analysis, effectively identifying asynchronous (dissimilar) spectral behaviors in the voltage-induced SERS spectra, was used to improve the discrimination. When two spectra of a sample collected with application of +100 and +300 mV were adopted, the features of subsequent 2T2D slice spectra were characteristic, and discrimination of GB stone and GB polyp substantially improved. External voltage application and recognition of the voltage-induced spectral features by 2T2D correlation analysis were key factors for the improvement. Since the demonstrated method relied on only a few SERS-active compounds, infrared (IR) spectroscopy featuring all the present components in the samples was also evaluated for comparison. However, the IR-based discrimination was inferior because the metabolite compositions in the samples between the GB diseases were not noticeably different.

Biliary excretion of gadobenate dimeglumine causing degradation of magnetic resonance cholangiopancreatography (MRCP)

PURPOSE

To assess the effect of gadobenate dimeglumine on magnetic resonance cholangiopancreatography (MRCP) and determine an appropriate time frame for performing MRCP sequences.

MATERIALS AND METHODS

2D MRCP sequences obtained after intravenous administration of gadobenate dimeglumine or gadobutrol over 14 months were reviewed retrospectively in randomized order by five abdominal radiologists, using a 3-point scale to rate biliary and pancreatic duct clarity (1 = no-, 2 = limited-, 3 = good visualization). Intraclass correlation coefficients were computed and mean scores were compared for both agents. For gadobenate dimeglumine exams, time delays between arterial phase and MRCP acquisition times were analyzed concerning duct clarity. For gadobutrol, only exams with delays ≥ 15 min were included.

RESULTS

134 exams (107 gadobenate dimeglumine, 27 gadobutrol) were included. Moderate reliability for pancreatic duct visualization and excellent reliability for visualization of intrahepatic bile ducts and upper and lower extrahepatic bile ducts were noted. No difference in mean scores was noted for pancreatic duct visualization (p = 0.66). Bile duct segment scores were lower with gadobenate dimeglumine (mean: 2.1-2.6) compared with gadobutrol (mean: 2.8-2.9) (p ≤ 0.006). For gadobenate dimeglumine, visualization scores varied depending on the delay between the arterial phase and MRCP acquisition (p ≤ 0.047). Good visualization for all bile duct segments was noted with delays of 7.2-9.4 min (95% confidence interval; mean 8.3 min).

CONCLUSION

Bile duct clarity degraded on MRCP images with an increasing delay following gadobenate dimeglumine injection. 2D MRCP, thus, should be performed within 7.2 min after obtaining the arterial phase sequence to ensure good visualization of the entire biliary system.

Feasibility of Voltage-Applied SERS Measurement of Bile Juice as an Effective Analytical Scheme to Enhance Discrimination between Gall Bladder (GB) Polyp and GB Cancer

A unique surface-enhanced Raman scattering (SERS) measurement scheme to discriminate gall bladder (GB) polyp and GB cancer by analysis of bile juice is proposed. Along with the high sensitivity of SERS, external voltage application during SERS measurement was incorporated to improve sample discriminability. For this purpose, Au nanodendrites were constructed on a screen-printed electrode (referred to as AuND@SPE), and Raman spectra of extracted aqueous phases from raw bile juice samples were acquired using the AuND@SPE at voltages from -300 to 300 mV. The sample spectra resembled that of bilirubin, possessing an open chain tetrapyrrole, showing that bilirubin derivatives in bile juice were mainly responsible for the observed peaks. Discrimination of GB polyp and GB cancer using just the normal SERS spectra was not achieved but became apparent when the spectra were acquired at a voltage of -100 mV. When voltage-applied SERS spectra of bilirubin and urobilinogen (one of bilirubin's derivatives) were examined, a sudden intensity elevation occurring at -100 mV was observed for urobilinogen but not bilirubin. Based on examination of corresponding cyclic voltammograms, the potential-driven strong adsorption of urobilinogen (no faradaic charge transfer) on AuND occurring at -100 mV induced a substantial increase in SERS intensity. It was presumed that the content of urobilinogen in the bile juice of a GB cancer patient would be higher than that of a GB polyp patient, and the contained urobilinogen was sensitively highlighted by applying -100 mV during SERS measurement, allowing clear discrimination of GB cancer against GB polyp.

Improved infrared spectroscopic discrimination between gall bladder (GB) polyps and GB cancer using component-descriptive spectral features of separated phases from bile

This study demonstrates a unique strategy for enhancing infrared (IR) spectroscopic discrimination between gall bladder (GB) polyps and cancer. This strategy includes the separation of raw bile juice into three sections of organic, aqueous, and amphiphilic phases and a cooperative combination of all IR spectral features of each separated phase for the discrimination. Raw bile juice is viscous and complex in composition because it contains fatty acids, cholesterol, proteins, phospholipids, bilirubin, and other components; therefore, the acquisition of IR spectra providing more component-discernible information is fundamental for improving discrimination. For this purpose, raw bile juice was separated into an aqueous phase, mostly containing bile salts, an organic phase with isolated lipids, and an amphiphilic phase, mainly containing proteins. The subsequent IR spectra of each separated phase were mutually characteristic and complementary to each other. When all the IR spectral features were combined, the discrimination was improved compared to that using the spectra of raw bile juice with no separation. The cooperative integration of more component-specific spectra obtained from each separated phase enhanced the discrimination. In addition, the IR spectra of the major constituents in bile juice, such as bile acids, conjugated bile salts, lecithin, and cholesterol, were recorded to explain the IR features of each separated phase.

The association between eating difficulties and biliary sludge in the gallbladder in older adults with advanced dementia, at end of life

Objectives

In clinical settings, untreatable biliary sludge in the gallbladder can be observed in older adults with advanced dementia. The underlying cause of biliary sludge existence in patients with dementia is currently unknown. Therefore, we aimed to investigate the prevalence, risk factors, and related outcomes of biliary sludge formation in the gallbladder of older adults with dementia.

Design

Cross-sectional study.

Setting

Geriatric ward of University Hospital in Japan.

Participants

Inpatients aged 80 and older living with dementia.

Measurements

We evaluated the presence of biliary sludge by diagnostic ultrasonography and collected data regarding patient demographic information, cognition (mini-mental state examination [MMSE]), physical activity (Barthel Index), oral food intake (food intake level scale [FILS]), clinical stage of dementia (functional assessment staging [FAST] of dementia), and patient performance status (Zubrod/ Karnofsky score).

Results

Male sex, larger gallbladder volume and calories from oral intake were significantly associated with the presence of biliary sludge (P = .02, .02, .002, respectively). There was a significant negative correlation between the FAST stage and the FILS level in all patients (P < .001). More advanced dementia and dysphagia was more likely to be found in patients with Alzheimer disease (AD) with biliary sludge, compared to patients with AD without biliary sludge (FAST 7a, FILS II and FAST 6c, FILS V, respectively, P = .06, 04). A logistic regression analysis revealed that the eating status of FILS I and II, generally called “fasting or anorexia”, was a significant risk factor for forming biliary sludge in older adults with dementia (P = .031, odds ratio: 5.25, 95% confidence interval: 1.16–23.72).

Conclusions

Fasting status may be associated with the existence of biliary sludge in older adults with dementia. Therefore, supportive care for eating might be an important solution to comfortable end-of-life care for older adults with advanced dementia.

Role of the biliary microbiome in gallstone disease

Gallstone disease is caused by multiple pathogenic factors and is common worldwide. Most studies have focused on the significance of the biliary microbiome in gallstone pathogenesis. Areas covered: In this study, the epidemiology of gallstone diseases and the existence, composition, origin, and mechanisms of the biliary microbiota were reviewed. Mechanisms involved in promoting the formation of different types of gallstones were also emphasized. The antibiotic susceptibility of the biliary microbiota is briefly discussed because it may guide clinical strategies. Expert commentary: The biliary microbiome facilitates the formation of brown pigment stones. Although glycoprotein (mucin) may be pivotal for many promoting substances to coagulate and integrate relevant components, new mechanisms involving prostaglandins, oxysterols, oxygen free radicals, and lipopolysaccharides have been discovered. Furthermore, specific bacterial species such as Helicobacter and Salmonella are involved in the pathogenesis of cholesterol gallstones. Recently, metabolomics of the biliary microbiome has been used to determine the detailed mechanisms that promote gallstone formation. Previously, the bacterial effects involved in the pathogenesis of brown pigment stones have not been analyzed in detail. Whether the administration of antibiotics is related to prophylaxis for gallstone formation and gallstone-associated infections remains unclear.

Clinical Importance and Natural History of Biliary Sludge in Outpatients

OBJECTIVES

Gallbladder sludge is a common diagnosis on routine abdominal sonography, yet its clinical importance is uncertain, especially in outpatients. To determine its natural history and potential future complications in this setting, we reviewed the imaging and clinical histories of nonhospitalized patients with a diagnosis of sludge on sonography.

METHODS

We conducted a retrospective search of our institutional radiology information system for all sonographic reports using the key words "biliary sludge without gallstones" over a 3-year period. For each of the 104 patients with isolated biliary sludge on initial sonography, we reviewed the electronic medical records and all imaging for the development of pancreaticobiliary complications.

RESULTS

We found an overall prevalence of biliary sludge in outpatients of 1.8%. Of the 104 patients reviewed with a mean follow up of 630 days (21 months), 25 developed a pancreaticobiliary complication, including cholelithiasis, cholecystitis, choledocholithiasis, and pancreatitis. The most frequent complication was cholecystitis, with a total of 14 diagnoses (12 chronic acalculous and 2 acute with gallstones). An additional 6 patients developed gallstones without cholecystitis features; 4 patients developed pancreatitis; and 1 developed choledocholithiasis. Biliary sludge remained quiescent or resolved in 76% of patients.

CONCLUSIONS

Biliary sludge always represents a pathologic process, but its clinical implications among outpatients have not been previously investigated. Our ambulatory population developed pancreaticobiliary complications at similar rates as prior mixed-patient setting studies. Regardless of the patient setting, biliary sludge is likely of more clinical importance than previously regarded.

Type 2 diabetes mitigation in the diabetic Goto-Kakizaki rat by elevated bile acids following a common-bile-duct surgery

OBJECTIVE

Elevated plasma bile acids after bariatric surgery are thought to explain type 2 diabetes mellitus (T2DM) remission. Bile acids can bind to and activate the nuclear receptor farnesoid-X receptor (FXR) by regulating lipid and glucose metabolism. We performed a surgical procedure (ligation of the common bile duct and external biliary drainage [LBD]) in the diabetic Goto-Kakizaki (GK) rat in order to investigate its effect on bile acids metabolism and T2DM mitigation.

MATERIAL/METHODS

LBD surgery and sham control surgery were performed on diabetic GK rats. The concentrations of total bile acids and blood glucose were analyzed by an automatic analyzer. Intraperitoneal glucose tolerance test (IPGTT) and insulin tolerance test (ITT) were used to monitor blood glucose level. Expression of genes involved in bile acid metabolism (FXR, CYP7A, et al.) and glycolipid metabolism (G6Pase, PEPCK, et al) was analyzed using qRT-PCR. The protein levels of pAKT, AKT and pGSK3β were tested by western blot. The morphological alterations of the liver and epididymal fat were monitored by H&E staining.

RESULTS

LBD increased plasma total bile acids, improved hepatic insulin sensitivity, and eventually mitigated T2DM, whereas food intake and body weight were unaltered. Post-LBD, the levels of total bile acids were elevated from 24.80±7.12 to 61.44±6.40 and the concentration of fast blood glucose was decreased from 204.7±11.06mg/dL to 109.3±5.4mg/dL. IPGTT and ITT showed that LBD operation improved insulin sensitivity in GK rats. Clusters of FXR signaling target genes were altered in the liver, such as FXR, CYP7A, G6Pase and PEPCK. These contributed to sustained bile acid homeostasis, and they ameliorated hepatic endoplasmic reticulum (ER) stress, increased energy expenditure, and reduced gluconeogenesis, resulting in a substantial improvement in hepatic insulin sensitivity. LBD also significantly reduced epididymal fat tissue and decreased the size of adipocytes.

CONCLUSION

These results demonstrate that the elevated bile acids observed in LBD-operated GK rats link insulin sensitivity improvement to T2DM mitigation, recapitulating the metabolic effects of bariatric surgery. Our investigation establishes a model for a focused study of bile acids in the context of bariatric surgery that may contribute to the identification of therapeutics for T2DM.