Total Bile Salt Research Articles

Understanding the Impact of Lipids on the Solubilizing Capacity of Human Intestinal Fluids.

Lipids in human intestinal fluids (HIF) form various structures, resulting in phase separation in the form of a lipid fraction and a micellar aqueous fraction. Currently used fed state simulated intestinal fluids (SIF) lack phase separation, highlighting the need for a deeper understanding of the effect of these fractions on intestinal drug solubilization in HIF to improve simulation accuracy. In this study, duodenal fluids aspirated from 21 healthy volunteers in fasted, early fed, and late fed states were used to generate 7 HIF pools for each prandial state. The apparent solubility of seven lipophilic model drugs was measured across these HIF pools, differentiating between the micellar fraction and the total sample (including both micellar and lipid fractions). The solubilizing capacities of these fluids were analyzed in relation to their composition, including total lipids, bile salts, phospholipids, total cholesterol, pH, and total protein. The solubility data generated in this work demonstrated that current fed state SIF effectively predicted the average solubility in the micellar fraction of HIF but failed to discern the considerable variability between HIF pools. Furthermore, the inclusion of a lipid fraction significantly enhanced the solubility of fed state HIF pools, resulting on average in a 13.9-fold increase in solubilizing capacity across the seven model compounds. Although the average composition of the fluids was consistent with previous studies, substantial variability was observed in micellar lipid concentrations, despite relatively stable total lipid concentrations. This variability is critical, as evidenced by the strong correlations between the solubilizing capacity of the micellar fraction and its micellar lipid concentrations. Additionally, this study identified that fluctuations in bile salt concentrations and pH contributed to the observed variability in micellar lipid concentration. In summary, the influence of the lipid fraction on solubility was 2-fold: it enhanced the solubility of lipophilic drugs in the total fluid, and contributed to the variability in the solubilizing capacity of the micellar fraction.

Interfacial behaviour of human bile and its substitution for in vitro lipolysis studies

This study examined the interfacial evolution of individual bile salts (BSs) and their blends with phosphatidylcholine (BS/PC) to simulate the complex behaviour of human bile (HB) during lipolysis at the triglyceride/water interface. Using adsorption and desorption cycles, mimicking exposure to small intestinal fluids, we demonstrate that the interfacial behaviour of real HB can be replicated using simple mixtures of BSs and PC. Interfacial tension (IFT) measurements after lipolysis and desorption showed no significant differences (P > 0.05) between HB samples and BS/PC mixtures across the total BS concentrations analysed (2.23–7.81 mM). However, individual BSs without PC yielded significantly different IFT results (P < 0.01) compared to HB, highlighting the importance of phospholipids. Dilatation rheology further emphasised the need for accurate phospholipid representation in bile models. Our results suggest that phospholipids in HB and in BS/PC systems enhance resistance to desorption, potentially affecting lipolysis. This is important, as current in vitro digestion models often replicate only intestinal BS concentrations to mimic the behaviour of HB in the intestinal lumen. Furthermore, the specific composition of BSs in HB appears less critical than the overall BS and phospholipid contents, suggesting that the kinetics of triglyceride digestion is influenced by the combined luminal concentrations of these components. These findings have significant implications for understanding the role of bile in digestion and offer insights for designing more accurate in vitro models to study the gastrointestinal behaviour of food emulsions and lipid-based delivery systems.

Microbiota-Liver-Bile Salts Axis, a Novel Mechanism Involved in the Contrasting Effects of Sodium Selenite and Selenium-Nanoparticle Supplementation on Adipose Tissue Development in Adolescent Rats.

Adolescence is a period during which body composition changes deeply. Selenium (Se) is an excellent antioxidant trace element related to cell growth and endocrine function. In adolescent rats, low Se supplementation affects adipocyte development differently depending on its form of administration (selenite or Se nanoparticles (SeNPs). Despite this effect being related to oxidative, insulin-signaling and autophagy processes, the whole mechanism is not elucidated. The microbiota-liver-bile salts secretion axis is related to lipid homeostasis and adipose tissue development. Therefore, the colonic microbiota and total bile salts homeostasis were explored in four experimental groups of male adolescent rats: control, low-sodium selenite supplementation, low SeNP supplementation and moderate SeNPs supplementation. SeNPs were obtained by reducing Se tetrachloride in the presence of ascorbic acid. Supplementation was received orally through water intake; low-Se rats received twice more Se than control animals and moderate-Se rats tenfold more. Supplementation with low doses of Se clearly affected anaerobic colonic microbiota profile and bile salts homeostasis. However, these effects were different depending on the Se administration form. Selenite supplementation primarily affected liver by decreasing farnesoid X receptor hepatic function, leading to the accumulation of hepatic bile salts together to increase in the ratio Firmicutes/Bacteroidetes and glucagon-like peptide-1 (GLP-1) secretion. In contrast, low SeNP levels mainly affected microbiota, moving them towards a more prominent Gram-negative profile in which the relative abundance of Akkermansia and Muribaculaceae was clearly enhanced and the Firmicutes/Bacteroidetes ratio decreased. This bacterial profile is directly related to lower adipose tissue mass. Moreover, low SeNP administration did not modify bile salts pool in serum circulation. In addition, specific gut microbiota was regulated upon administration of low levels of Se in the forms of selenite or SeNPs, which are properly discussed. On its side, moderate-SeNPs administration led to great dysbiosis and enhanced the abundance of pathogenic bacteria, being considered toxic. These results strongly correlate with the deep change in adipose mass previously found in these animals, indicating that the microbiota-liver-bile salts axis is also mechanistically involved in these changes.

Fluorofenidone ameliorates cholestasis and fibrosis by inhibiting hepatic Erk/-Egr-1 signaling and Tgfβ1/Smad pathway in mice

Cholestasis is characterized by intrahepatic accumulation of bile acids (BAs), resulting in liver injury, fibrosis, and liver failure. To date, only ursodeoxycholic acid and obeticholic acid have been approved for the treatment of cholestasis. As fluorofenidone (AKF-PD) was previously reported to play significant anti-fibrotic and anti-inflammatory roles in various diseases, we investigated whether AKF-PD ameliorates cholestasis. A mouse model of cholestasis was constructed by administering a 0.1 % 3,5-diethoxycarbonyl-1,4-dihydroxychollidine (DDC) diet for 14 days. Male C57BL/6 J mice were treated with either AKF-PD or pirfenidone (PD) orally in addition to the DDC diet. Serum and liver tissues were subsequently collected and analyzed. We found that AKF-PD significantly reduced the levels of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and total bile salts (TBA), as well as hepatic bile acids (BAs) levels. Hepatic histological analyses demonstrated that AKF-PD markedly attenuated hepatic inflammation and fibrosis. Further mechanistic analyses revealed that AKF-PD markedly inhibited expression of Cyp7a1, an enzyme key to BAs synthesis, by increasing Fxr nuclear translocation, and decreased hepatic inflammation by attenuating Erk/-Egr-1-mediated expression of inflammatory cytokines and chemokines Tnfα, Il-1β, Il-6, Ccl2, Ccl5 and Cxcl10. Moreover, AKF-PD was found to substantially reduce liver fibrosis via inhibition of Tgfβ1/Smad pathway in our mouse model. Here, we found that AKF-PD effectively attenuates cholestasis and hepatic fibrosis in the mouse model of DDC-induced cholestasis. As such, AKF-PD warrants further investigation as a candidate drug for treatment of cholestasis.

The bile salt content of human bile impacts on simulated intestinal proteolysis of β-lactoglobulin

The gastrointestinal hydrolysis of food proteins has been portrayed in scientific literature to predominantly depend on the activity and specificity of proteolytic enzymes. Human bile has not been considered to facilitate proteolysis in the small intestine, but rather to assist in intestinal lipolysis. However, human bile can potentially influence proteins that are largely resistant to gastric digestion, and which are mainly hydrolysed after they have been transferred to the small intestine. We used purified and food-grade bovine milk β-lactoglobulin (βLg) to assess the impact of bile salts (BS) on the in vitro gastrointestinal digestion of this protein. Quantitative analysis showed that the proteolysis rate increased significantly with increasing BS concentration. The effect was consistent regardless of whether individual BS or real human bile samples, varying in BS concentrations, were used. The total BS content of bile was more important than its BS composition in facilitating the proteolysis of βlg. We also show that the impact of human bile observed during the digestion of purified βLg and βLg-rich whey protein isolate can be closely replicated by the use of individual BS mixed with phosphatidylcholine. This could validate simple BS/phosphatidylcholine mixtures as human-relevant substitutes of difficult-to-obtain human bile for in vitro proteolysis studies.

Postprandial rise of essential amino acids is impaired during critical illness and unrelated to small‐intestinal function

BackgroundPostprandial rise of plasma essential amino acids (EAAs) determines the anabolic effect of dietary protein. Disturbed gastrointestinal function could impair the anabolic response in critically ill patients. Aim was to investigate the postprandial EAA response in critically ill patients and its relation to small‐intestinal function.MethodsTwenty‐one mechanically ventilated patients and 9 healthy controls received a bolus containing 100 ml of a formula feed (Ensure) and 2 g of 3‐O‐Methyl‐d‐glucose (3‐OMG) via postpyloric feeding tube. Fasting and postprandial plasma concentrations of EAAs, 3‐OMG, total bile salts, and the gut‐released hormone fibroblast growth factor 19 (FGF19) were measured over a 4‐hour period. Changes over time and between groups were assessed with linear mixed‐effects analysis. Early (0–60 minutes) and total postprandial responses are summarized as the incremental area under the curve (iAUC).ResultsAt baseline, fasting EAA levels were similar in both groups: 1181 (1055–1276) vs 1150 (1065–1334) μmol·L−1, P = .87. The early postprandial rise in EAA was not apparent in critically ill patients compared with healthy controls (iAUC60, −4858 [−6859 to 2886] vs 5406 [3099–16,853] µmol·L−1·60 minutes; P = .039). Impaired EAA response did not correlate with impaired 3‐OMG response (Spearman ρ 0.32, P = .09). There was a limited increase in total bile salts but no relevant FGF19 response in either group.ConclusionPostprandial rise of EAA is blunted in critically ill patients and unrelated to glucose absorption measured with 3‐OMG. Future studies should aim to delineate governing mechanisms of macronutrient malabsorption.

Bile Salt and FGF19 Signaling in the Early Phase of Human Liver Regeneration.

The involvement of bile salt–fibroblast growth factor 19 (FGF19) signaling in human liver regeneration (LR) is not well studied. Therefore, we studied aspects of bile salt–FGF19 signaling shortly after liver resection in patients. We compared plasma bile salt and FGF19 levels in arterial, portal and hepatic venous blood, calculated venous‐arterial differences (ΔVA), and determined hepatic transcript levels on two intra‐operative time points: before (< 1 hour) and immediately after (> 2‐3 hours) liver resection (i.e., following surgery). Postoperative bile salt and FGF19 levels were assessed on days 1, 2, and 3. LR was studied by computed tomography (CT)–liver volumetry. Following surgery, the liver, arterial, and portal bile salt levels were elevated (P < 0.05). Furthermore, an increased amount of bile salts was released in portal blood and extracted by the remnant liver (P < 0.05). Postoperatively, bile salt levels were elevated from day 1 onward (P < 0.001). For FGF19, intra‐operative or postoperative changes of ΔVA or plasma levels were not observed. The bile salt–homeostatic regulator farnesoid X receptor (FXR) was markedly up‐regulated following surgery (P < 0.001). Cell‐cycle re‐entry priming factors (interleukin 6 [IL‐6], signal transducer and activator of transcription 3 [STAT3], and cJUN) were up‐regulated following surgery and were positively correlated with FXR expression (P < 0.05). Postoperative hyperbilirubinemia was preceded by postsurgery low FXR and high Na+/Taurocholate cotransporting polypeptide (NTCP) expression in the remnant liver coupled with higher liver bile salt content (P < 0.05). Finally, bile salt levels on postoperative day 1 were an independent predictor of LR (P < 0.05). Conclusion: Systemic, portal, and liver bile salt levels are rapidly elevated after liver resection. Postoperative bile salts were positively associated with liver volume gain. In the studied time frame, FGF19 levels remained unaltered, suggesting that FGF19 plays a minor role in human LR. These findings indicate a more relevant role of bile salts in human LR.

Obstetric Cholestasis: A Review and Update

Obstetric cholestasis (OC) is a liver disorder that occurs in the late second and early third trimester of pregnancy characterized by pruritus with increased serum bile acids and other liver function tests. The pathophysiology of OC is still not completely understood. The symptoms and biochemical abnormality rapidly resolve after delivery. OC is associated with an increased risk of adverse obstetrical outcomes. The aetiology of obstetric cholestasis of pregnancy is poorly understood and is thought to be complicated and multifactorial. OC typically occurs in the late second trimester when the oestrogen levels are the highest in pregnancy. The most common complaint is generalized intense pruritus, which usually starts after the 30th week of pregnancy. Pruritus can be more common in the palms and soles and is typically worse at night. Other symptoms of cholestasis, such as nausea, anorexia, fatigue, right upper quadrant pain, dark urine, and pale stool, can be present. Clinical jaundice is rare but may present in 14% to 25% of patients after 1 to 4 weeks of the onset of pruritus. Some patients also complain of insomnia as a result of pruritus. Generally, physical examination is unremarkable except for scratch marks on the skin from pruritus. Pruritus is a cardinal symptom of intra-hepatic cholestasis of pregnancy (ICP) and may precede biochemical abnormalities. The diagnosis of intrahepatic cholestasis of pregnancy is via the presence of clinical symptoms pruritus in the third trimester with elevated maternal total serum bile acids and excluding other diagnoses, which can cause similar symptoms and lab abnormalities. Fasting blood samples should be used to check for the total bile salt acid level as it can become elevated in the postprandial state.&#x0D; Once the diagnosis of OC of pregnancy is confirmed, immediate treatment is necessary, and the primary goal of therapy is to decrease the risk of perinatal morbidity and mortality and to alleviate maternal symptoms. Maternal pruritus can be alleviated with use of moisturisers and oral antihistamines. Ursodeoxycholic acid (UDCA) is the drug of choice for the treatment of ICP.&#x0D; Many authors have advocated elective early delivery of women with intrahepatic cholestasis of pregnancy to reduce the risk of sudden foetal death. The Royal College of Obstetricians and Gynaecologists recommends induction of labour after 37+0 weeks of gestation. Obstetric cholestasis of pregnancy is not an indication for Caesarean delivery. Postpartum pruritus typically disappears in the first 2 to 3 days following delivery, and serum bile acid concentrations will normalize eventually. ICP is not a contraindication to breastfeeding, and mothers with a history of ICP in pregnancy can breastfeed their infants. Postpartum monitoring and follow up of bile acids and liver function tests should be done in 4-6 weeks to ensure resolution. Women with the persistent abnormality of liver function test after 6 to 8 weeks require investigation for other aetiologies.

Multidimensional analysis of human intestinal fluid composition

The oral administration of solid dosage forms is the commonest method to achieve systemic therapy and relies on the drug’s solubility in human intestinal fluid (HIF), a key factor that influences bioavailability and biopharmaceutical classification. However, HIF is difficult to obtain and is known to be variable, which has led to the development of a range of simulated intestinal fluid (SIF) systems to determine drug solubility in vitro. In this study we have applied a novel multidimensional approach to analyse and characterise HIF composition using a published data set in both fasted and fed states with a view to refining the existing SIF approaches. The data set provided 152 and 172 measurements of five variables (total bile salt, phospholipid, total free fatty acid, cholesterol and pH) in time-dependent HIF samples from 20 volunteers in the fasted and fed state, respectively. The variable data sets for both fasted state and fed state are complex, do not follow normal distributions but the amphiphilic variable concentrations are correlated. When plotted 2-dimensionally a generally ellipsoid shaped data cloud with a positive slope is revealed with boundaries that enclose published fasted or fed HIF compositions. The data cloud also encloses the majority of fasted state and fed state SIF recipes and illustrates that the structured nature of design of experiment (DoE) approaches does not optimally cover the variable space and may examine media compositions that are not biorelevant. A principal component analysis in either fasted or fed state in combination with fitting an ellipsoid shape to enclose the data results in 8 points that capture over 95% of the compositional variability of HIF. The variable’s average rate of concentration change in both fasted state and fed state over a short time scale (10 min) is zero and a Euclidean analysis highlights differences between the fasted and fed states and among individual volunteers. The results indicate that a 9-point DoE (8 + 1 central point) could be applied to investigate drug solubility in vitro and provide statistical solubility limits. In addition, a single point could provide a worst-case solubility measurement to define the lowest biopharmaceutical classification boundary or for use during drug development. This study has provided a novel description of HIF composition. The approach could be expanded in multiple ways by incorporation of further data sets to improve the statistical coverage or to cover specific patient groups (e.g., paediatric). Further development might also be possible to analyse information on the time dependent behaviour of HIF and to guide HIF sampling and analysis protocols.

Is dietary taurine required for white seabream (Diplodus sargus) juveniles?

This study assessed the effect of supplementation of low-fishmeal (FM) diets with taurine in white seabream (Diplodus sargus) juveniles. Four isoproteic (36% CP) and isolipidic (18% CL) diets were formulated to include 15%FM or 5%FM, supplemented or not with 1% of Taurine (TAU). Twelve groups of 15 fish (IBW = 58 g) were fed each diet to near satiation for 10 weeks. Growth performance, feed intake, and feed efficiency were not affected by dietary FM level. Nevertheless, dietary TAU supplementation increased growth performance and feed efficiency. Nitrogen and energy retention were improved by both dietary FM level and TAU supplementation. Plasma cholesterol, lactate, and bilirubin did not differ among dietary treatments, but dietary TAU supplementation decreased plasma glucose and triglycerides levels. Decrease of FM level reduced total bile salts while TAU supplementation had the opposite effect. No differences were noticed in innate immune parameters assessed. Overall, results indicate that white seabream can be fed with diets almost devoid of FM, and that dietary TAU supplementation increases growth performance and feed efficiency. Moreover, results suggest that dietary TAU was limiting both in 15% and 5% FM diets.

Low-Dose Lipopolysaccharide Causes Biliary Injury by Blood Biliary Barrier Impairment in a Rat Hepatic Ischemia/Reperfusion Model.

This study explored whether bacterial endotoxins, in the form of lipopolysaccharides (LPS), could have an injurious effect on the biliary tract in conjunction with ischemia. A total of 64 rats were randomly assigned to 4 groups: sham operation (sham group), 1 mg/kg LPS intraperitoneal (LPS group), hepatic ischemia/reperfusion (IR; IR group), and IR combined with LPS (IR+LPS group). Following 1 or 6 hours of reperfusion, serum liver tests, bile duct histology, immunofluorescence microscopy (zonula occludens-1 [ZO-1]), bile composition (bile salts, phospholipids, lactate dehydrogenase), hepatic gene expression (bile salt transporters and inflammatory mediators), as well as serum and biliary cytokine concentrations were quantified and compared between the study groups. In addition, the integrity of the blood biliary barrier (BBB) was assayed in vivo using horseradish peroxidase (HRP). LPS administration induced severe small bile duct injury following 6 hours of reperfusion. Furthermore, total bile salts and bilirubin concentrations in serum were increased in the LPS groups compared with sham controls (LPS, + 3.3-fold and +1.9-fold; IR+LPS, + 3.8-fold and +1.7-fold, respectively). The BBB was impaired in the LPS groups as evidenced by elevated levels of HRP in bile (+4.9-fold), and decreased expression of claudin 1 (-6.7-fold) and claudin 3 (-3.6-fold). LPS was found to be a potent inducer of small bile duct injury following hepatic ischemia and 6 hours of reperfusion. This injury was associated with increased permeability of the BBB and impaired hepatic bile salt clearance. Liver Transplantation 23 194-206 2017 AASLD.

Intrahepatic cholestasis of pregnancy : Rare but important

Intrahepatic cholestasis of pregnancy (ICP) is aliver-specific disorder occurring in approximately 0.5-2.0% of all pregnancies with aconsiderable variation in certain ethnic groups. ICP usually runs abenign course for the mother and is characterized by maternal pruritus mainly in the third trimester, elevated transaminases and fasting total serum bile salts and increased fetal adverse events. The etiology of ICP is only partially understood but seems to be multifactorial. Cholestasis-inducing effects of certain female sex hormones and their metabolites play an important role in genetically susceptible women. The mechanisms resulting in fetal complications such as spontaneous preterm labour, antepartum passage of meconium, asphyxia events, still birth and fetal death are not well understood. Certain sulfated progesterone metabolites are likely to play arole in the pathogenesis of pruritus in ICP. In contrast to pregnancy-related dermatoses, pruritus does not present with primary skin alterations. However, intense scratching may cause secondary skin changes such as abrasions, excoriations and sometimes prurigo nodularis. Treatment is based on ursodeoxycholate treatment to reduce pruritus and hepatic impairment as well as elective delivery between gestation week 37-38 to pre-empt potential stillbirths. This article reviews clinical symptoms, diagnosis, treatment and in particular pathogenesis of pruritus in ICP.

Biliary excretion of pravastatin and taurocholate in rats with bile salt export pump (Bsep) impairment.

The bile salt export pump (BSEP) is expressed on the canalicular membrane of hepatocytes regulating liver bile salt excretion, and impairment of BSEP function may lead to cholestasis in humans. This study explored drug biliary excretion, as well as serum chemistry, individual bile acid concentrations and liver transporter expressions, in the SAGE Bsep knockout (KO) rat model. It was observed that the Bsep protein in KO rats was decreased to 15% of that in the wild type (WT), as quantified using LC-MS/MS. While the levels of Ntcp and Mrp2 were not significantly altered, Mrp3 expression increased and Oatp1a1 decreased in KO animals. Compared with the WT rats, the KO rats had similar serum chemistry and showed normal liver transaminases. Although the total plasma bile salts and bile flow were not significantly changed in Bsep KO rats, individual bile acids in plasma and liver demonstrated variable changes, indicating the impact of Bsep KO. Following an intravenous dose of deuterium labeled taurocholic acid (D4-TCA, 2mg/kg), the D4-TCA plasma exposure was higher and bile excretion was delayed by approximately 0.5h in the KO rats. No differences were observed for the pravastatin plasma concentration-time profile or the biliary excretion after intravenous administration (1mg/kg). Collectively, the results revealed that these rats have significantly lower Bsep expression, therefore affecting the biliary excretion of endogenous bile acids and Bsep substrates. However, these rats are able to maintain a relatively normal liver function through the remaining Bsep protein and via the regulation of other transporters. Copyright © 2016 John Wiley & Sons, Ltd.

ATP11C targets basolateral bile salt transporter proteins in mouse central hepatocytes.

ATP11C is a homolog of ATP8B1, both of which catalyze the transport of phospholipids in biological membranes. Mutations in ATP8B1 cause progressive familial intrahepatic cholestasis type1 in humans, which is characterized by a canalicular cholestasis. Mice deficient in ATP11C are characterized by a conjugated hyperbilirubinemia and an unconjugated hypercholanemia. Here, we have studied the hypothesis that ATP11C deficiency interferes with basolateral uptake of unconjugated bile salts, a process mediated by organic anion-transporting polypeptide (OATP) 1B2. ATP11C localized to the basolateral membrane of central hepatocytes in the liver lobule of control mice. In ATP11C-deficient mice, plasma total bilirubin levels were 6-fold increased, compared to control, of which ∼65% was conjugated and ∼35% unconjugated. Plasma total bile salts were 10-fold increased and were mostly present as unconjugated species. Functional studies in ATP11C-deficient mice indicated that hepatic uptake of unconjugated bile salts was strongly impaired whereas uptake of conjugated bile salts was unaffected. Western blotting and immunofluorescence analysis demonstrated near absence of basolateral bile salt uptake transporters OATP1B2, OATP1A1, OATP1A4, and Na(+) -taurocholate-cotransporting polypeptide only in central hepatocytes of ATP11C-deficient liver. In vivo application of the proteasome inhibitor, bortezomib, partially restored expression of these proteins, but not their localization. Furthermore, we observed post-translational down-regulation of ATP11C protein in livers from cholestatic mice, which coincided with reduced OATP1B2 levels. ATP11C is essential for basolateral membrane localization of multiple bile salt transport proteins in central hepatocytes and may act as a gatekeeper to prevent hepatic bile salt overload. Conjugated hyperbilirubinemia and unconjugated hypercholanemia and loss of OATP expression in ATP11C-deficient liver strongly resemble the characteristics of Rotor syndrome, suggesting that mutations in ATP11C can predispose to Rotor syndrome. (Hepatology 2016;64:161-174).

Ginsenoside Rg1 prevents cerebral and cerebellar injury induced by obstructive jaundice in rats via inducing expression of TIPE-2

The aim of the study was to analyze the effect of Ginsenoside Rg1 (Rg1) on cerebral and cerebellar injury in experimental obstructive jaundice (OJ). OJ was done by ligature and section of extrahepatic biliary duct. Rg1 was injected intraperitoneally (10mgkg−1d−1 or 20mgkg−1d−1). Comparison of serum total bile salts (TBA), total bilirubin (TBil), direct bilirubin (DBil), TNF-α, IL-6 and IL-1β among groups. Malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were determined, also apoptosis and mRNA and protein levels of TIPE2 (TNF-α-inducible protein 8-like 2) were tested in cerebrum and cerebellum. Our results showed that Rg1 reduced MDA and apoptosis in cerebrum and cerebellum induced by OJ, also GSH and antioxidant enzyme activity were raised obviously in rats treated with Rg1. Moreover, decreased mRNA and protein levels of TIPE2 in OJ rats and Rg1 could improve the decreased mRNA and protein levels of TIPE2 in OJ rats. In conclusion, Rg1 decreased oxidative stress and apoptosis, also recovered the antioxidant status and mRNA and protein levels of TIPE2 in the cerebrum and cerebellum of OJ rats.

The safety and efficacy of nasobiliary drainage in the treatment of refractory cholestatic pruritus: a multicentre European study.

Pruritus is a common symptom associated with cholestatic liver diseases. To date only small single centre case series have suggested efficacy of nasobiliary drainage in relieving cholestatic pruritus. To perform a multicentre study to evaluate the safety and efficacy of nasobiliary drainage in cholestatic pruritus. This was a retrospective study of all patients treated with nasobiliary drainage for refractory cholestatic pruritus between 2006 and 2015 at five European centres. Pruritus was quantified using a visual analogue scale (VAS) and liver enzymes, serum bilirubin and total serum bile salts (TBS) were measured before (pre-NBD) and after nasobiliary drainage (post-NBD). We analysed the duration of treatment response and associated complications. In total, 27 patients (59% females) underwent 29 nasobiliary drainage procedures. The median duration of NBD was 7 days. NBD decreased pruritus in 89.6% of cases (VAS from 10.0 to 0.3, P < 0.0001). The median percentage decline in pruritus VAS was 94% and 33% of patients were free of pruritus within 24 h of starting drainage. The duration of treatment response was independent of duration of drainage (P = 0.12) and bile output. Significant improvements were seen in the median levels of serum alkaline phosphatase (P = 0.001) and serum bilirubin (P = 0.03) but not in serum TBS (P = 0.07). Mild post-endoscopic retrograde cholangiopancreatography pancreatitis (31%) was the most frequent complication. Nasobiliary drainage is effective in relieving cholestatic pruritus in most patients and has favourable effect on biomarkers of cholestasis. Nasobiliary drainage may be associated with high risk of adverse events, especially pancreatitis. Prospective studies are needed to confirm our findings.

Altered intestinal bile salt biotransformation in a cystic fibrosis (Cftr−/−) mouse model with hepato-biliary pathology

BackgroundCftr−/−tm1Unc mice develop progressive hepato-biliary pathology. We hypothesize that this liver pathology is related to alterations in biliary bile hydrophobicity and bile salt metabolism in Cftr−/−tm1Unc mice. MethodsWe determined bile production, biliary and fecal bile salt- and lipid compositions and fecal bacterial composition of C57BL/6J Cftr−/−tm1Unc and control mice. ResultsWe found no differences between the total biliary bile salt or lipid concentrations of Cftr−/− and controls. Compared to controls, Cftr−/− mice had a ~30% higher bile production and a low bile hydrophobicity, related to a ~7 fold higher concentration of the choleretic and hydrophilic bile salt ursocholate. These findings coexisted with a significantly smaller quantity of fecal Bacteroides bacteria. ConclusionsLiver pathology in Cftr−/−tm1Unc is not related to increased bile hydrophobicity. Cftr−/− mice do however display a biliary phenotype characterized by increased bile production and decreased biliary hydrophobicity. Our findings suggest Cftr dependent, alterations in intestinal bacterial biotransformation of bile salts.

Autotaxin activity has a high accuracy to diagnose intrahepatic cholestasis of pregnancy

Intrahepatic cholestasis of pregnancy (ICP) is defined by pruritus, elevated total fasting serum bile salts (TBS) and transaminases, and an increased risk of adverse fetal outcome. An accurate diagnostic marker is needed. Increased serum autotaxin correlates with cholestasis-associated pruritus. We aimed at unraveling the diagnostic accuracy of autotaxin in ICP. Serum samples and placental tissue were collected from 44 women with uncomplicated pregnancies and 105 with pruritus and/or elevated serum transaminases. Autotaxin serum levels were quantified enzymatically and by Western blotting, autotaxin gene expression by quantitative PCR. Serum autotaxin was increased in ICP (mean ± SD: 43.5 ± 18.2 nmol ml(-1)min(-1), n=55, p<0.0001) compared to other pruritic disorders of pregnancy (16.8 ± 6.7 nmol ml(-1)min(-1), n=33), pre-eclampsia complicated by HELLP-syndrome (16.8 ± 8.9 nmol ml(-1)min(-1), n=17), and pregnant controls (19.6 ± 5.7 nmol ml(-1)min(-1), n=44). Longitudinal analysis during pregnancy revealed a marked rise in serum autotaxin with onset of ICP-related pruritus. Serum autotaxin was increased in women taking oral contraceptives. Increased serum autotaxin during ICP was not associated with increased autotaxin mRNA in placenta. With a cut-off value of 27.0 nmol ml(-1)min(-1), autotaxin had an excellent sensitivity and specificity in distinguishing ICP from other pruritic disorders or pre-eclampsia/HELLP-syndrome. Serum autotaxin displayed no circadian rhythm and was not influenced by food intake. Increased serum autotaxin activity represents a highly sensitive, specific and robust diagnostic marker of ICP, distinguishing ICP from other pruritic disorders of pregnancy and pregnancy-related liver diseases. Pregnancy and oral contraception increase serum autotaxin to a much lesser extent than ICP.

Comparative evaluation of in vitro efficacy of colesevelam hydrochloride tablets

Context: Colesevelam hydrochloride is used as an adjunct to diet and exercise to reduce elevated low-density lipoprotein (LDL) cholesterol in patients with primary hyperlipidemia as well as to improve glycemic control in patients with type 2 diabetes. This is likely to result in submission of abbreviated new drug applications (ANDA).Objective: This study was conducted to compare the efficacy of two tablet products of colesevelam hydrochloride based on the in vitro binding of bile acid sodium salts of glycocholic acid (GC), glycochenodeoxycholic acid (GCDA) and taurodeoxycholic acid (TDCA).Methods: Kinetic binding study was carried out with constant initial bile salt concentrations as a function of time. Equilibrium binding studies were conducted under conditions of constant incubation time and varying initial concentrations of bile acid sodium salts. The unbound concentration of bile salts was determined in the samples of these studies. Langmuir equation was utilized to calculate the binding constants k1 and k2.Results: The amount of the three bile salts bound to both the products reached equilibrium at 3 h. The similarity factor (f2) was 99.5 based on the binding profile of total bile salts to the test and reference colesevelam tablets as a function of time. The 90% confidence interval for the test to reference ratio of k2 values were 96.06–112.07 which is within the acceptance criteria of 80–120%.Conclusion: It is concluded from the results that the test and reference tablets of colesevelam hydrochloride showed a similar in vitro binding profile and capacity to bile salts.

Characterization of fasted human gastric fluid for relevant rheological parameters and gastric lipase activities

PurposeTo characterize human gastric fluid with regard to rheological properties and gastric lipase activity. In addition, traditional physicochemical properties were determined. MethodsFasted HGA were collected from 19 healthy volunteers during a gastroscopic examination. Rheological characterization of the aspirates was conducted on a TA AR-G2 rheometer, using cone and plate geometry. Lipase activity was measured by continuous titration of released free fatty acid from tributyrate. Further, pH, osmolality, buffer capacity, and surface tension were measured and the total protein content and bile salt level were determined using assay kits. ResultsRheological examination of HGA showed non-Newtonian shear-thinning behavior with predominant elastic behavior in the linear range. The apparent viscosity was measured to be in the range of 1.7–9.3mPas at a shear rate of 50s−1. The FaSSGF and HCl pH 1.2 have no shear-thinning properties and showed lower viscosity (1.1mPas at 50s−1). The observed viscosity of the HGA will decrease the intrinsic dissolution rate of drugs. The activity of the gastric lipase was 7.4±4.0U/mL (N=6, n=3) and 99.0±45.3U/mL (N=19, n=3) at pH 2.8 and 5.4, respectively. pH, surface tension, buffer capacity, bile salt concentration, and osmolality were measured and compared with literature data. ConclusionThe rheological behavior and the mean apparent viscosity of HGA are significantly different from that of water and should therefore be considered important during development of gastric simulated media. Further, the activity of the HGL is active even under fasted gastric conditions and might contribute to the digestion and emulsification of lipid-based drug delivery systems in the entire gastrointestinal tract. HGL should therefore be considered in gastric evaluation of lipid-based drug delivery systems.