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

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

Effect of an Emulsified Formulation on Vegetable Carotenoid Bioaccessibility.

We investigated the effect of neutral lipids, polar lipids, and an emulsified formulation (EMF) on carotenoid bioaccessibility in an in vitro digestion assay of vegetables. These reagents enhanced carotenoid bioaccessibility. Contrary to our previous report, they also exhibited effects on lutein. Bile extracts/pancreatin concentrations also participated in the bioaccessibility. The EMF, which consisted of lower amounts of oil, had the same effect on lutein as rapeseed oil. These reagents also showed effects in the aging model, with more reduced bile extract/pancreatin concentrations, suggesting that lipids and EMF contributed to carotenoid bioaccessibility in bile/pancreatic juice secretions due to aging and disease.

Exploring the Bile Stress Response of Lactobacillus mucosae LM1 through Exoproteome Analysis.

Lactobacillus sp. have long been studied for their great potential in probiotic applications. Recently, proteomics analysis has become a useful tool for studies on potential lactobacilli probiotics. Specifically, proteomics has helped determine and describe the physiological changes that lactic acid bacteria undergo in specific conditions, especially in the host gut. In particular, the extracellular proteome, or exoproteome, of lactobacilli contains proteins specific to host- or environment-microbe interactions. Using gel-free, label-free ultra-high performance liquid chromatography tandem mass spectrometry, we explored the exoproteome of the probiotic candidate Lactobacillus mucosae LM1 subjected to bile treatment, to determine the proteins it may use against bile stress in the gut. Bile stress increased the size of the LM1 exoproteome, secreting ribosomal proteins (50S ribosomal protein L27 and L16) and metabolic proteins (lactate dehydrogenase, phosphoglycerate kinase, glyceraldehyde-3-phosphate dehydrogenase and pyruvate dehydrogenases, among others) that might have moonlighting functions in the LM1 bile stress response. Interestingly, membrane-associated proteins (transporters, peptidase, ligase and cell division protein ftsH) were among the key proteins whose secretion were induced by the LM1 bile stress response. These specific proteins from LM1 exoproteome will be useful in observing the proposed bile response mechanisms via in vitro experiments. Our data also reveal the possible beneficial effects of LM1 to the host gut.

Bile formation and secretion: An update.

Bile formation is a fundamental physiological process that is vital to the survival of all vertebrates. However, little was known about the mechanisms of this secretion until after World War II. Initial studies involved classic physiologic studies in animal models and humans, which progressed to include studies in isolated cells and membrane vesicles. The advent of molecular biology then led to the identification of specific transport systems that are the determinants of this secretion. Progress in this field was reviewed in the American Physiologic Society's series on "Comprehensive Physiology" in 2013. Herein, we provide an in-depth update of progress since that time.

Randomised clinical trial: significant biochemical and colonic transit effects of the farnesoid X receptor agonist tropifexor in patients with primary bile acid diarrhoea.

BACKGROUND: In primary bile acid diarrhoea, feedback by farnesoid X receptor (FXR) and fibroblast growth hormone 19 (FGF19) on hepatic bile acid production is impaired. AIMS: To evaluate the safety, mechanisms and efficacy of negative feedback by FXR activation with tropifexor, a non-bile acid FXR agonist, in patients with primary bile acid diarrhoea. METHODS: In this double-blind, multicentre, randomised, cross-over study, patients received tropifexor 60 µg or placebo once daily for 14 days in each of two treatment periods. Primary objectives included tropifexor safety and tolerability, and on stool frequency and form. Other assessments included pharmacokinetic and pharmacodynamic measures, biochemical markers and gastrointestinal transit. RESULTS: Twenty patients (tropifexor 60 µg/placebo [N = 10]; placebo/tropifexor 60 µg [N = 10]) were enrolled. Adverse event rates were lower with tropifexor vs placebo (52.9% vs 73.7%). No patient had pruritus during tropifexor intake. There were no significant differences in stool frequency, stool form or loperamide use between treatments. Tropifexor increased FGF19 and decreased 7α-hydroxy-4-cholesten-3-one (C4) levels for up to 8 h. Plasma tropifexor concentrations peaked at 5 hours post-dose on days 1 and 12. At day 12, tropifexor caused reduction in peak total bile acid concentration (33%, P = 0.032) and exposure (36%, P = 0.005). Moreover, tropifexor showed a significant increase in ascending colon half-emptying time (P = 0.036). CONCLUSIONS: Tropifexor 60 µg once daily had acceptable safety and tolerability. Changes in FGF19 and C4 showed effective target engagement; however, higher doses may be required to observe stool frequency changes. Slowing of ascending colon emptying suggests therapeutic potential of tropifexor in patients with primary bile acid diarrhoea. ClinicalTrials.gov number: NCT02713243.

La vesícula biliar como reservorio y protectora del tracto digestivo / The gallbladder as reservoir and protector of the digestive tract

Introducción: Estudios anatomofisiológicos y biomoleculares de la vesícula biliar han permitido redefinir su función no solo como reservorio de la secreción biliar, sino como protectora intestinal, concepto que se fundamenta en su capacidad de control de la bioactividad y la toxicología de los ácidos biliares, el metabolismo del colesterol, los fosfolípidos y otros componentes de la secreción hepatobiliar. Objetivo: Describir las actualidades de la funcionabilidad de la vesícula biliar como reservorio y protectora del tracto digestivo dirigido a que cirujanos generales, gastroenterólogos, clínicos y fisiólogos amplíen sus conocimientos sobre la función de la vesícula biliar. Métodos: Se realiza una revisión crítica de las funciones de la vesícula biliar que favorecen mantener la integridad de la pared intestinal. Conclusión: La descripción actualizada de la funcionabilidad de la vesícula biliar ofrece un resultado relevante dentro del marco conceptual en relación a su función protectora que se traduce en el mantenimiento de la integridad del epitelio y la microbiota intestinal(AU)

Introduction: Anatomic-physiological and biomolecular studies of the gallbladder have made it possible to redefine its function not only as a reservoir for bile secretion, but also as intestinal protector. This concept is supported by its capacity to control the bioactivity and toxicology of bile acids, cholesterol metabolism, phospholipids and other components of hepatobiliary secretion. Objective: Present an update on the role of the gallbladder as reservoir and protector of the digestive tract intended for general surgeons, gastroenterologists, clinicians and physiologists to broaden their knowledge about the functions of the gallbladder. Methods: A critical review was conducted of the functions of the gallbladder which facilitate maintenance of the integrity of the intestinal wall. Conclusion: The updated description of the functions of the gallbladder is a relevant contribution to the conceptual framework of its protective function, which ensures the maintenance of the integrity of the epithelium and the intestinal microbiota(AU)

Hepatic Bile Formation: Canalicular Osmolarity and Paracellular and Transcellular Water Flow.

The purpose of this minireview is to show that a new paradigm is developing regarding hepatic bile flow. The focus thus far has been on carrier-mediated transport of bile acids and other solutes, such as glutathione, which create an osmotic gradient for the transcellular and paracellular flow of water into canaliculi. In addition to the physicochemical properties of bile acids, which govern the osmotic gradient, data now exist showing that the tight junctions governing paracellular water flow and Aquaporin-8 water channels governing transcellular water flow are regulated independently. Thus, the rate of water flow into the canaliculus in response to bile acid transport is variable and determines canalicular bile acid concentration, which affects the production and solubilization of cholesterol-lecithin vesicles. These new considerations modify thinking regarding the occurrence of cholestasis and its progression and reorient the design of experimental studies that can distinguish the different determinants of bile flow. SIGNIFICANCE STATEMENT: The paradigm that water flow into the canaliculus is determined only by the rate of carrier-mediated transport has been challenged recently by the changes that occur in hepatic bile composition in the Claudin-2 knockout mouse and with the cholestatic effect of estradiol 17ß-d-glucuronide. Thus, a respective reduction in paracellular or transcellular canalicular water flow, probably via Aquaporin 8, has no significant effect on bile acid excretion.

A fully coupled porous media and channels flow approach for simulation of blood and bile flow through the liver lobules.

Two dimensional, steady state, and incompressible blood and bile flows through the liver lobules are numerically simulated. Two different geometric models A and B are proposed to study the effects of lobule structure on the fluid flow behaviour. In Model A, the lobule tissue is represented as a hexagonal shape porous medium with a set of flow channels at its vertices accounting for the hepatic artery, portal and central veins along with bile ductules. Model B is a channelized porous medium constructed by adding a set of flow channels, representing the bile canaliculies and lobule sinusoids, to Model A. The bile and blood flow through the lobule is simulated by the finite element approach, based on the Darcy/Brinkman equations in the lobule tissue and the Navier-Stokes (or Stokes) equations in the flow channels. In Model B, a transmission factor on the boundaries of the bile canaliculies is introduced to connect the bile and blood flows. First, a single regular lobule is utilized to exhibit the fluid flow pattern through the liver lobule represented by proposed geometric models. Then, the model is extended to a group of liver lobules to demonstrate the flow through a liver slice represented by irregular lobules. Numerical results indicate that the Darcy and Brinkman equations provide nearly the same solutions for Model A and similar solutions with a little difference for Model B. It is shown that the existence of sinusoids and bile canaliculies inside the liver lobules has noticeable effects on its fluid flow pattern, in terms of pressure and velocity fields.

Enhancement of bile resistance by maltodextrin supplementation in Lactobacillus plantarum Lp-115.

AIMS: To identify the mechanism in which way maltodextrin enhance bile tolerance in Lactobacillus plantarum Lp-115. METHODS AND RESULTS: Based on determining the OD600 value and counting the numbers of viable cells by the pour plate method, the results showed that maltodextrin could not promote the strain growth directly, but could enhance the tolerance of bile in Lp-115. The OD600 value of L. plantarum Lp-115 cultured in MRSB broth with maltodextrin was three times higher than the control value. After supplementing the medium with 4·0% maltodextrin, the highest survival rate was observed when the bile concentration is 0.3%. CONCLUSIONS: In summary, maltodextrin exhibited a significant improvement of bile tolerance and it could enhance cell hydrophobicity, shift the fatty acid composition of the membrane and induce the expression of a bile salt hydrolase gene (pva3) significantly. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report concerning the mechanism of maltodextrin enhancing the bile tolerance. This study promotes the application of maltodextrin as a choice to protect probiotic L. plantarum strains against the bile salt stress.

Identification of a novel function of hepatic long-chain acyl-CoA synthetase-1 (ACSL1) in bile acid synthesis and its regulation by bile acid-activated farnesoid X receptor.

Long-chain acyl-CoA synthetase 1 (ACSL1) plays a pivotal role in fatty acid ß­oxidation in heart, adipose tissue and skeletal muscle. However, key functions of ACSL1 in the liver remain largely unknown. We investigated acute effects of hepatic ACSL1 deficiency on lipid metabolism in adult mice under hyperlipidemic and normolipidemic conditions. We knocked down hepatic ACSL1 expression using adenovirus expressing a ACSL1 shRNA (Ad-shAcsl1) in mice fed a high-fat diet or a normal chow diet. Hepatic ACSL1 depletion generated a hypercholesterolemic phenotype in mice fed both diets with marked elevations of total cholesterol, LDL-cholesterol and free cholesterol in circulation and accumulations of cholesterol in the liver. Furthermore, SREBP2 pathway in ACSL1 depleted livers was severely repressed with a 50% reduction of LDL receptor protein levels. In contrast to the dysregulated cholesterol metabolism, serum triglycerides, free fatty acid and phospholipid levels were unaffected. Mechanistic investigations of genome-wide gene expression profiling and pathway analysis revealed that ACSL1 depletion repressed expressions of several key enzymes for bile acid biosynthesis, consequently leading to reduced liver bile acid levels and altered bile acid compositions. These results are the first demonstration of a requisite role of ACSL1 in bile acid biosynthetic pathway in liver tissue. Furthermore, we discovered that Acsl1 is a novel molecular target of the bile acid-activated farnesoid X receptor (FXR). Activation of FXR by agonist obeticholic acid repressed the expression of ACSL1 protein and mRNA in the liver of FXR wild-type mice but not in FXR knockout mice.

Evaluation of valve function in antireflux biliary metal stents.

BACKGROUND: To overcome duodenobiliary reflux induced by biliary stents, antireflux valve (ARV) biliary stents have been developed and showed improvement in stent patency. However, negative study results have also been reported because stent patency may be decreased by the malfunction of ARV itself. Given such mixed results, the true efficacy of ARV remains unknown and the mechanism of its dysfunction needs to be clearly elucidated. The aim of this study was to investigate the exact mechanism of ARV dysfunction using in vitro phantom models. METHODS: Two experimental models were designed to evaluate two important environmental factors suspected to cause ARV malfunction, i.e. bile flow and pH. Three types of ARV metal stents from different companies were used for the experiments: a funnel type ARV, a windsock type ARV, and a wine glass-shaped ARV. Ten stents of each type were tested (five stents in the bile flow phantom model, and another five stents in the duodenal pH environmental model). To determine ARV malfunction, ARV-induced flow resistance was measured using a custom-made testing device. All stents from the two models were removed every 2 weeks for 12 weeks after stent insertion and were evaluated on morphological and functional changes of the ARV. RESULTS: Only ARV of wine glass-shaped ARV was morphologically changed due to silicone bond detachment in the bile flow model. All types of ARV were morphologically changed in the pH model. The morphological changes of ARV influenced the flow resistance. The antegrade pressure gradients were increased over time in the pH model (p < 0.05). CONCLUSIONS: Morphological change of the ARVs may induce dysfunction of ARV metal stents, which is mainly due to duodenal pH environment. In the future, development of new ARV that is not affected by duodenal environmental factors can be expected to improve stent patency.

Proper bile duct flow, rather than radical excision, is the most critical factor determining treatment outcomes of bile duct cysts.

BACKGROUND: The purpose of this study was to compare the impact of the extent of excision and the patent bile duct flow on treatment outcomes of bile duct cysts (BDCs). METHODS: We retrospectively analyzed the records of 382 patients who received surgery for BDCs from January 2005 to December 2014. RESULTS: For Type Ia cysts, proper bile flow was associated with good long-term treatment outcomes with a greater level of significance (p < 0.001) than complete excision (p = 0.012). For Type IVa cysts, proper bile flow, but not complete excision, was associated with good long-term outcomes (p < 0.00001). In addition, 96.3% (104/108) of Type IVa patients with proper bile flow had no late complications and good biliary function, while no patient without patent bile flow had a good clinical outcome. For Type Ic cysts, 92 patients who received partial excisions had good outcomes when proper bile flow was restored. Regression analysis revealed that the absence of proper bile flow, in comparison to incomplete excision, is a greater risk factor for poor long-term treatment effects for Type Ia and Type IVa cysts. CONCLUSIONS: Compared to complete excision, the establishment of proper bile flow exerted a greater impact on improving long-term clinical outcomes after BDC surgery.

Biliary tract external drainage improves inflammatory mediators and pathomorphology of the intestine, liver, and lung in septic rats.

BACKGROUND: To investigate the effect of biliary tract external drainage (BTED) on inflammatory mediators and pathomorphism of intestine, liver, and lung in septic rats. METHOD: 48 SD rats (n = 8 per group) were randomized into six groups: control, sepsis, sepsis plus BTED, normal bile (obtained from eight healthy rats), and septic bile infusion for 6 hours respectively to test the effects of BTED bile infusion on cytokines' expression and tissue injury in the intestine, liver, and lung of septic/normal rats. Co-cultivation of intestinal epithelial cells (IEC-6) with bile for 12 hours was performed to evaluate the potential cytotoxicity of septic bile. Survival rate for sepsis plus BTED rats was detected compared with sepsis without BTED group (n = 20 per group) at 24, 48, and 72 hours, respectively. RESULTS: BTED for 6 hours significantly reduced the mRNA expression levels of tumor necrosis factor alpha (TNF-α) and IL-1ß (all p < 0.05 vs. sepsis group), whereas mRNA expression of TNF-α and IL-1ß in the intestine was increased after 6 hours' septic bile infusion compared with normal bile infusion group (all p < 0.05). TNF-α concentration in septic bile was significantly higher than that in the control group (p < 0.001). Tissue injury was significantly attenuated after 6 hours' BTED. CONCLUSIONS: BTED can significantly restrain the mRNA expression of TNF-α and IL-1ß in the intestine, liver, and lung and attenuate histological damage in septic rats.

Bile Gastritis Following Laparoscopic Single Anastomosis Gastric Bypass: Pilot Study to Assess Significance of Bilirubin Level in Gastric Aspirate.

INTRODUCTION: Laparoscopic single anastomosis gastric bypass (SAGB) is increasingly performed for morbidly obese patients. AIM OF WORK: This pilot study aims primarily at evaluating the incidence of bile gastritis after SAGB. The occurrence of reflux oesophagitis and reflux symptoms were also assessed. PATIENTS AND METHODS: This study included 20 patients having no reflux symptoms. All patients underwent a SAGB as a primary bariatric procedure by a single surgeon. Patients included consented to have an upper GI endoscopy done at 6 months postoperatively. Gastric aspirate was sent for bilirubin level assessment. Gastric and esophageal biopsies were submitted for histopathology and campylobacter-like organism (CLO) test. RESULTS: In our study, the rate of bile gastritis was 30%. In 18 patients, the level of bilirubin in gastric aspirate seems to be related to the degree of mucosal inflammation. The remaining two patients had microscopic moderate to severe gastritis with normal aspirate bilirubin level. Two patients with bilirubin level in aspirate more than 20 mg/dl had severe oesophagitis, gastritis with erosions, and metaplasia. Relationship between bilirubin level and histopathological findings of gastric biopsy examination was statistically significant with a P value of 0.001. CONCLUSION: The incidence of bile gastritis in this cohort is higher than reported in the literature, and this may be worrying. The correlation between endoscopic findings and patients' symptoms is poor. Bilirubin level and pH in aspirate might be useful tools to confirm alkaline reflux. Its level might help to choose candidates for revision surgery after SAGB. This needs further validation with larger sample size.

Short communication: Lactose enhances bile tolerance of yogurt culture bacteria.

Lactose is an energy source for culture bacteria. Bile tolerance is an important probiotic property. Our aim was to elucidate the effect of lactose on bile tolerance of yogurt starter culture Lactobacillus bulgaricus LB-12 and Streptococcus thermophilus ST-M5. Bile tolerance of pure cultures was determined using 0.3% oxgall in MRS THIO broth (Difco, Becton Dickinson, Sparks, MD) for L. bulgaricus and 0.3% oxgall in M17 broth (Oxoid, Basingstoke, UK) for Strep. thermophilus. Lactose was added to both broths at 0 (control), 1, 3, and 5% (wt/vol) broth. Dilutions were plated hourly for 12 h. Experiments were replicated 3 times. At 2, 4, and 12 h of incubation, lactose incorporated at all amounts, 1, 3, and 5% (wt/vol), showed higher counts of Strep. thermophilus ST-M5 compared with the control. Lactose use at 5% (wt/vol) significantly enhanced bile tolerance of both L. bulgaricus and Strep. thermophilus compared with control.

Experiencing, Exploiting, and Evacuating Bile: Framing Fashionable Biliousness from the Sufferer's Perspective.

This article examines how sufferers experienced, understood, and expressed themselves as bilious, focusing on the late Georgian era when the disease became one of the most fashionable and oft diagnosed amongst the elites. We show that responses to bile were more complex, varied, and less credulous than contemporary diatribes and subsequent historiography imply. Nonetheless, we foreground the socioculturally negotiated elements of the malady rather than its "reality." Applying Rosenberg's framing diseases model reveals biliousness as one of the most problematic conditions to frame, but one of the most malleable to self-fashion. We demonstrate how Georgian Britons found functionality in their bile and "performed" being bilious. Articulate, literate sufferers deployed a range of strategies to vent or master their bile, or to render it social and serviceable, deriving various compensatory "secondary gains." We illuminate their variable success in reifying and sublimating bile, and differentiating the boundaries of biliousness vis-à-vis other complaints.

Resistant starch can improve insulin sensitivity independently of the gut microbiota.

BACKGROUND: Obesity-related diseases, including type 2 diabetes and cardiovascular disease, have reached epidemic proportions in industrialized nations, and dietary interventions for their prevention are therefore important. Resistant starches (RS) improve insulin sensitivity in clinical trials, but the mechanisms underlying this health benefit remain poorly understood. Because RS fermentation by the gut microbiota results in the formation of physiologically active metabolites, we chose to specifically determine the role of the gut microbiota in mediating the metabolic benefits of RS. To achieve this goal, we determined the effects of RS when added to a Western diet on host metabolism in mice with and without a microbiota. RESULTS: RS feeding of conventionalized mice improved insulin sensitivity and redressed some of the Western diet-induced changes in microbiome composition. However, parallel experiments in germ-free littermates revealed that RS-mediated improvements in insulin levels also occurred in the absence of a microbiota. RS reduced gene expression of adipose tissue macrophage markers and altered cecal concentrations of several bile acids in both germ-free and conventionalized mice; these effects were strongly correlated with the metabolic benefits, providing a potential microbiota-independent mechanism to explain the physiological effects of RS. CONCLUSIONS: This study demonstrated that some metabolic benefits exerted by dietary RS, especially improvements in insulin levels, occur independently of the microbiota and could involve alterations in the bile acid cycle and adipose tissue immune modulation. This work also sets a precedent for future mechanistic studies aimed at establishing the causative role of the gut microbiota in mediating the benefits of bioactive compounds and functional foods.

The Role of Acid Suppression in Barrett's Esophagus.

In recent years, proton pump inhibitors (PPIs) have come under great scrutiny due to possible adverse, long-term side effects. At the same time, Barrett's esophagus, a premalignant condition in the esophagus, continues to be a disease whose course is thought to be improved by the use of PPIs. We review the impact of proton pump therapy on the esophagus and on Barrett's mucosa. In analyzing changes on a cellular level, we explore the effect of mixed gastric refluxate and the complex cascade that ensues with esophageal exposure of these contents. Because the incidence of esophageal adenocarcinoma is on the rise, we explore other factors that may contribute to the progression of Barrett's from non-dysplastic mucosa to esophageal adenocarcinoma. By revisiting the need for adequate acid suppression in Barrett's and increasing our understanding of other possible factors that may have an effect of Barrett's progression, we hope to support our multifaceted approach to acid suppression in patients with Barrett's esophagus.