Hepatocellular transporters and cholestasis

Novel approach for reconstruction of the three-dimensional biliary system in decellularized liver scaffold using hepatocyte progenitors

Reconstruction of the biliary system is indispensable for the regeneration of transplantable liver grafts. Here, we report the establishment of the first continuous three-dimensional biliary system scaffold for bile acid excretion using a novel method. We confirmed the preservation of the liver-derived extracellular matrix distribution in the scaffold. In addition, hepatocyte progenitors decellularized via the bile duct by slow-speed perfusion differentiated into hepatocyte- and cholangiocyte-like cells, mimicking hepatic cords and bile ducts, respectively. Furthermore, qRT-PCR demonstrated increased ALB, BSEP, and AQP8 expression, revealing bile canaliculi- and bile duct-specific genetic patterns. Therefore, we concluded that locally preserved extracellular matrices in the scaffold stimulated hepatic progenitors and provided efficient differentiation, as well as regeneration of a three-dimensional continuous biliary system from hepatic cords through bile ducts. These findings suggest that organ-derived scaffolds can be utilized for the efficient reconstruction of functional biliary systems.

A systemic lupus erythematosus patient with persistent elevated conjugated bilirubin as the initial symptom: A case report

RATIONALE

While some systemic lupus erythematosus (SLE) patients may experience varying degrees of liver function abnormalities, only a small portion of these cases have clinical significance, and the majority of patients typically exhibit low levels of serum bilirubin. However, in this article, we present a case of a middle-aged female patient with SLE who exhibited persistent skin jaundice as her initial symptom, offering a fresh perspective on diagnosing and treating patients who exhibit unexplained liver dysfunction and SLE combined with liver injury.

PATIENT CONCERNS

A 45-year-old woman was initially admitted to the hospital due to yellowing of the skin and sclera, and her symptoms did not improve significantly during treatment. The results were abnormal after relevant immunological tests.

DIAGNOSES

Persistent non-conjugated bilirubin elevation due to lupus hepatitis.

INTERVENTIONS

The use of methylprednisolone sodium succinate (40 mg/Qd) and mycophenolate mofetil (0.75 g/d) suppressed immunity, polyolefin choline (20 mL/d) and glutathione (0.6 g/Qd) improved liver function, and nutritional support therapy.

OUTCOMES

After 2 weeks of treatment, a significant decrease in the yellow skin and sclera of the patient was observed.

LESSONS

Most clinicians overlook that liver function abnormalities are the main manifestation of SLE, resulting in many patients not receiving timely treatment. This study highlights the importance that SLE is also a cause of abnormal liver function.

Liver's influence on the brain through the action of bile acids

The liver partakes as a sensor and effector of peripheral metabolic changes and a regulator of systemic blood and nutrient circulation. As such, abnormalities arising from liver dysfunction can influence the brain in multiple ways, owing to direct and indirect bilateral communication between the liver and the brain. Interestingly, altered bile acid composition resulting from perturbed liver cholesterol metabolism influences systemic inflammatory responses, blood-brain barrier permeability, and neuron synaptic functions. Furthermore, bile acids produced by specific bacterial species may provide a causal link between dysregulated gut flora and neurodegenerative disease pathology through the gut-brain axis. This review will cover the role of bile acids-an often-overlooked category of active metabolites-in the development of neurological disorders associated with neurodegeneration. Further studies into bile acid signaling in the brain may provide insights into novel treatments against neurological disorders.

Modulation of Disordered Bile Acid Homeostasis and Hepatic Tight Junctions Using Salidroside against Hepatocyte Apoptosis in Furan-Induced Mice

Furan, a processing-induced food contaminant, has attracted great attention due to its hepatotoxicity. To further investigate the underlying mechanism of salidroside (SAL) alleviating furan-induced liver damage, we divided Balb/c mice into the control group, the furan (8 mg/kg/day) group, and three groups of three different doses of SAL (10/20/40 mg/kg/day) in the current research. The shifted serum profile was observed through untargeted metabonomics, to which the bile acid metabolism was related, and the alleviating effect of SAL against furan-induced apoptosis was caused by the metabolism. Target bile acid quantification for the liver and serum showed that SAL positively regulated the homeostasis of bile acids disturbed by furan. Meanwhile, SAL significantly upregulated the synthesis genes of bile acids (Cyp7a1, Cyp7b1, Cyp8b1, and Cyp27a1) and the uptake transport genes (Ntcp and Oatps) and downregulated the efflux transport genes (Bsep, Ost-α, Ost-β, Mrp2, and Mrp4). Transmission electron microscopy of the bile canaliculi and tight junctions and the levels of tight junction marker proteins (ZO-1, occludin, and claudin-1) confirmed that the disruption of the hepatic tight junction was inhibited by SAL. The connection between the apoptosis- and tight junction-related proteins was observed through the construction of a protein-protein interaction network. SAL suppressed the furan-induced hepatocyte apoptosis evidenced by the detection of TUNEL and Bax, Bcl-2, and caspase-3 levels. Taken together, SAL alleviated furan-induced hepatocyte apoptosis via altering the disordered homeostasis of bile acids and hepatic tight junctions.

Gut Microbiome-Linked Metabolites in the Pathobiology of Major Depression With or Without Anxiety—A Role for Bile Acids

Background

The gut microbiome may play a role in the pathogenesis of neuropsychiatric diseases including major depressive disorder (MDD). Bile acids (BAs) are steroid acids that are synthesized in the liver from cholesterol and further processed by gut-bacterial enzymes, thus requiring both human and gut microbiome enzymatic processes in their metabolism. BAs participate in a range of important host functions such as lipid transport and metabolism, cellular signaling and regulation of energy homeostasis. BAs have recently been implicated in the pathophysiology of Alzheimer's and several other neuropsychiatric diseases, but the biochemical underpinnings of these gut microbiome-linked metabolites in the pathophysiology of depression and anxiety remains largely unknown.

Method

Using targeted metabolomics, we profiled primary and secondary BAs in the baseline serum samples of 208 untreated outpatients with MDD. We assessed the relationship of BA concentrations and the severity of depressive and anxiety symptoms as defined by the 17-item Hamilton Depression Rating Scale (HRSD₁₇) and the 14-item Hamilton Anxiety Rating Scale (HRSA-Total), respectively. We also evaluated whether the baseline metabolic profile of BA informs about treatment outcomes.

Results

The concentration of the primary BA chenodeoxycholic acid (CDCA) was significantly lower at baseline in both severely depressed (log₂ fold difference (LFD) = −0.48; p = 0.021) and highly anxious (LFD = −0.43; p = 0.021) participants compared to participants with less severe symptoms. The gut bacteria-derived secondary BAs produced from CDCA such as lithocholic acid (LCA) and several of its metabolites, and their ratios to primary BAs, were significantly higher in the more anxious participants (LFD's range = [0.23, 1.36]; p's range = [6.85E-6, 1.86E-2]). The interaction analysis of HRSD₁₇ and HRSA-Total suggested that the BA concentration differences were more strongly correlated to the symptoms of anxiety than depression. Significant differences in baseline CDCA (LFD = −0.87, p = 0.0009), isoLCA (LFD = −1.08, p = 0.016) and several BA ratios (LFD's range [0.46, 1.66], p's range [0.0003, 0.049]) differentiated treatment failures from remitters.

Conclusion

In patients with MDD, BA profiles representing changes in gut microbiome compositions are associated with higher levels of anxiety and increased probability of first-line treatment failure. If confirmed, these findings suggest the possibility of developing gut microbiome-directed therapies for MDD characterized by gut dysbiosis.

Fraxinellone Induces Hepatotoxicity in Zebrafish through Oxidative Stress and the Transporters Pathway

Fraxinellone (FRA), a major active component from Cortex Dictamni, produces hepatotoxicity via the metabolization of furan rings by CYP450. However, the mechanism underlying the hepatotoxicity of FRA remains unclear. Therefore, zebrafish larvae at 72 h post fertilization were used to evaluate the metabolic hepatotoxicity of FRA and to explore the underlying molecular mechanisms. The results showed that FRA (10-30 μM) induced liver injury and obvious alterations in the metabolomics of zebrafish larvae. FRA induces apoptosis by increasing the level of ROS and activating the JNK/P53 pathway. In addition, FRA can induce cholestasis by down-regulating bile acid transporters P-gp, Bsep, and Ntcp. The addition of the CYP3A inhibitor ketoconazole (1 μM) significantly reduced the hepatotoxicity of FRA (30 μM), which indicated that FRA induced hepatotoxicity through CYP3A metabolism. Targeted metabolomics analysis indicates the changes in amino acid levels can be combined with molecular biology to clarify the mechanism of hepatotoxicity induced by FRA, and amino acid metabolism monitoring may provide a new method for the prevention and treatment of DILI from FRA.

Urinary BA Indices as Prognostic Biomarkers for Complications Associated with Liver Diseases

Hepatobiliary diseases and their complications cause the accumulation of toxic bile acids (BA) in the liver, blood, and other tissues, which may exacerbate the underlying condition and lead to unfavorable prognosis. To develop and validate prognostic biomarkers for the prediction of complications of cholestatic liver disease based on urinary BA indices, liquid chromatography-tandem mass spectrometry was used to analyze urine samples from 257 patients with cholestatic liver diseases during a 7-year follow-up period. The urinary BA profile and non-BA parameters were monitored, and logistic regression models were used to predict the prognosis of hepatobiliary disease-related complications. Urinary BA indices were applied to quantify the composition, metabolism, hydrophilicity, and toxicity of the BA profile. We have developed and validated the bile-acid liver disease complication (BALDC) model based on BA indices using logistic regression model, to predict the prognosis of cholestatic liver disease complications including ascites. The mixed BA and non-BA model was the most accurate and provided higher area under the receiver operating characteristic (ROC) and smaller akaike information criterion (AIC) values compared to both non-BA and MELD (models for end stage liver disease) models. Therefore, the mixed BA and non-BA model could be used to predict the development of ascites in patients diagnosed with liver disease at early stages of intervention. This will help physicians to make a better decision when treating hepatobiliary disease-related ascites.

Metabolic characteristics of plasma bile acids in patients with intrahepatic cholestasis of pregnancy-mass spectrometric study

INTRODUCTION

Intrahepatic cholestasis of pregnancy (ICP) is one of the more common complications in the middle and late stages of pregnancy, which requires early detection and intervention.

OBJECTIVE

The aim of the study is to investigate the changes in the metabolic profile of bile acids (BAs) in plasma of pregnant women with ICP and to look biomarkers for the diagnosis and grading of ICP, and to explore the disease mechanism.

METHODS

The targeted metabolomics based on high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was used to analyze plasma BAs.

RESULTS

Twenty-seven BAs can be quantified in all participants. Among them, 22 BAs were identified as differential BAs between ICP and control groups. Five BAs include 3β-CA, 3β-DCA, CDCA-3Gln, NCA, and Tβ-MCA, were found to be associated with ICP for the first time. Nine BAs include NCA, GCA, GCDCA, GHCA, GUDCA, HCA, TCA, TCDCA and THCA, can be used as possible ICP diagnostic biomarkers. Four BAs, i.e., GLCA, THCA, GHCA and TLCA-3S may be used as potential biomarkers for ICP grading.

CONCLUSION

There were significant differences in plasma BA profiles between ICP patients and the control. The BA profiles of mild ICP group and severe ICP group partially overlapped. Potential diagnostic and grading BA markers were identified. A significant characteristic of ICP group was the increase of conjugated BAs. A mechanism to sustain the equilibrium of BA metabolism and adaptive response has been developed in ICP patients to accelerate excretion and detoxification.

Locally advanced pancreatic carcinoma with jaundice: the benefit of a sequential treatment with stenting followed by CT-guided 125I seeds implantation

OBJECTIVES

To evaluate the role of sequential therapy with percutaneous biliary stenting and CT-guided iodine-125 seed implantation for locally advanced pancreatic carcinoma with concomitant obstructive jaundice.

METHODS

Between January 2016 and December 2018, 42 patients diagnosed with locally advanced pancreatic carcinoma with concomitant obstructive jaundice were enrolled retrospectively. All patients received biliary stenting via percutaneous transhepatic biliary drainage (PTBD) to alleviate obstructive jaundice. Thereafter, twenty-two patients underwent CT-guided iodine-125 seed implantation (treatment group), and 20 did not (control group). The prescribed dose in the treatment group was 110-130 Gy. The clinical data, duration of biliary stent patency, and overall survival (OS) were evaluated.

RESULTS

Overall, the total bilirubin level decreased from 275.89 ± 115.44 to 43.08 ± 43.35 μmol/L (p < 0.001) 1 month after percutaneous biliary stenting. In the treatment group, the postoperative median dose covering 90% of the target volume was 129.71 Gy. Compared with the control group, the treatment group had a long mean duration of biliary stent patency and median OS (11.42 vs. 8.57 months, p < 0.01; 11.67 vs. 9.40 months, p < 0.01, respectively). The overall positive response rates 6 months post-treatment in the treatment and control groups were 72.7% (16/22) and 30% (6/20), respectively. Adverse events of more than grade 3 were not observed during the follow-up.

CONCLUSION

Sequential therapy with percutaneous biliary stenting and CT-guided iodine-125 seed implantation is an effective and safe treatment alternative for locally advanced pancreatic carcinoma with concomitant obstructive jaundice, which is worthy of clinical application.

KEY POINTS

• Obstructive jaundice was alleviated after biliary stent placement in all patients, and the total bilirubin level decreased. • The overall positive response rates at 6 months post-treatment were higher in the treatment group than in the control group, and adverse events of more than grade 3 were not observed during the follow-up period. • Sequential therapy with percutaneous biliary stenting and CT-guided iodine-125 seed implantation can prolong biliary stent patency and improve survival.

Metal stents are safe and cost-effective for preoperative biliary drainage in resectable pancreaticobiliary tumours

BACKGROUNDS

To compare the complication rates and overall costs of self-expandable metal stents (SEMS) and plastic stents (PS) in clinically indicated preoperative biliary drainage (PBD) prior to a pancreatoduodenectomy (PD).

METHODS

We conducted an Australian multicentre retrospective cohort study using the databases of four tertiary hospitals. Adult patients who underwent clinically indicated endoscopic PBD prior to PD from 2010 to 2019 were included. Rates of complications attributable to PBD, surgical complications and pre-operative endoscopic re-intervention were calculated. Costing data were retrieved from our Financial department.

RESULTS

Among the 157 included patients (mean age 66.6 ± 9.8 years, 45.2% male), 49 (31.2%) received SEMS and 108 received PS (68.8%). Baseline bilirubin was 187.5 ± 122.6 μmol/L. Resection histopathology showed mainly adenocarcinoma (93.0%). Overall SEMS was associated less complications (12.2% vs. 28.7%, p = 0.02) and a lower pre-operative endoscopic re-intervention rate (4.3 vs. 20.8%, p = 0.03) compared with PS. There was no difference in post-PD complication rates. On multivariate logistic regression analysis, stent type was an independent risk factor of PBD complication (OR of SEMS compared to PS 0.24, 95% CI 0.07-0.79, p = 0.02) but not for any secondary outcome measures. Upfront material costs were $56USD for PS and $1991USD for SEMS. Accounting for rates of complications, average costs were similar ($3110USD for PS and $3026USD for SEMS).

CONCLUSION

In resectable pancreaticobiliary tumours, SEMS for PBD was associated with reduced risk of overall PBD-related complications and pre-surgical endoscopic reintervention rates and was comparable to PS in terms of overall cost.

Bile acid indices as biomarkers for liver diseases II: The bile acid score survival prognostic model

BACKGROUND

Cholestatic liver diseases are characterized by an accumulation of toxic bile acids (BA) in the liver, blood and other tissues which lead to progressive liver injury and poor prognosis in patients.

AIM

To discover and validate prognostic biomarkers of cholestatic liver diseases based on the urinary BA profile.

METHODS

We analyzed urine samples by liquid chromatography-tandem mass spectrometry and investigated the use of the urinary BA profile to develop survival models that can predict the prognosis of hepatobiliary diseases. The urinary BA profile, a set of non-BA parameters, and the adverse events of liver transplant and/or death were monitored in 257 patients with cholestatic liver diseases for up to 7 years. The BA profile was characterized by calculating BA indices, which quantify the composition, metabolism, hydrophilicity, formation of secondary BA, and toxicity of the BA profile. We have developed and validated the bile-acid score (BAS) model (a survival model based on BA indices) to predict the prognosis of cholestatic liver diseases.

RESULTS

We have developed and validated a survival model based on BA (the BAS model) indices to predict the prognosis of cholestatic liver diseases. Our results demonstrate that the BAS model is more accurate and results in higher true-positive and true-negative prediction of death compared to both non-BAS and model for end-stage liver disease (MELD) models. Both 5- and 3-year survival probabilities markedly decreased as a function of BAS. Moreover, patients with high BAS had a 4-fold higher rate of death and lived for an average of 11 mo shorter than subjects with low BAS. The increased risk of death with high vs low BAS was also 2-4-fold higher and the shortening of lifespan was 6-7-mo lower compared to MELD or non-BAS. Similarly, we have shown the use of BAS to predict the survival of patients with and without liver transplant (LT). Therefore, BAS could be used to define the most seriously ill patients, who need earlier intervention such as LT. This will help provide guidance for timely care for liver patients.

CONCLUSION

The BAS model is more accurate than MELD and non-BAS models in predicting the prognosis of cholestatic liver diseases.

Bile acid indices as biomarkers for liver diseases I: Diagnostic markers

BACKGROUND

Hepatobiliary diseases result in the accumulation of toxic bile acids (BA) in the liver, blood, and other tissues which may contribute to an unfavorable prognosis.

AIM

To discover and validate diagnostic biomarkers of cholestatic liver diseases based on the urinary BA profile.

METHODS

We analyzed urine samples by liquid chromatography-tandem mass spectrometry and compared the urinary BA profile between 300 patients with hepatobiliary diseases vs 103 healthy controls by statistical analysis. The BA profile was characterized using BA indices, which quantifies the composition, metabolism, hydrophilicity, and toxicity of the BA profile. BA indices have much lower inter- and intra-individual variability compared to absolute concentrations of BA. In addition, BA indices demonstrate high area under the receiver operating characteristic curves, and changes of BA indices are associated with the risk of having a liver disease, which demonstrates their use as diagnostic biomarkers for cholestatic liver diseases.

RESULTS

Total and individual BA concentrations were higher in all patients. The percentage of secondary BA (lithocholic acid and deoxycholic acid) was significantly lower, while the percentage of primary BA (chenodeoxycholic acid, cholic acid, and hyocholic acid) was markedly higher in patients compared to controls. In addition, the percentage of taurine-amidation was higher in patients than controls. The increase in the non-12α-OH BA was more profound than 12α-OH BA (cholic acid and deoxycholic acid) causing a decrease in the 12α-OH/ non-12α-OH ratio in patients. This trend was stronger in patients with more advanced liver diseases as reflected by the model for end-stage liver disease score and the presence of hepatic decompensation. The percentage of sulfation was also higher in patients with more severe forms of liver diseases.

CONCLUSION

BA indices have much lower inter- and intra-individual variability compared to absolute BA concentrations and changes of BA indices are associated with the risk of developing liver diseases.

Long noncoding RNAs-a new dimension in the molecular architecture of the bile acid/FXR pathway

Bile acids, regarded as the body's detergent for digesting lipids, also function as critical signaling molecules that regulate cholesterol and triglyceride levels in the body. Bile acids are the natural ligands of the nuclear receptor, FXR, which controls an intricate network of cellular pathways to maintain metabolic homeostasis. In recent years, growing evidence supports that many cellular actions of the bile acid/FXR pathway are mediated by long non-coding RNAs (lncRNAs), and lncRNAs are in turn powerful regulators of bile acid levels and FXR activities. In this review, we highlight the substantial progress made in the understanding of the functional and mechanistic role of lncRNAs in bile acid metabolism and how lncRNAs connect bile acid activity to additional metabolic processes. We also discuss the potential of lncRNA studies in elucidating novel molecular mechanisms of the bile acid/FXR pathway and the promise of lncRNAs as potential diagnostic markers and therapeutic targets for diseases associated with altered bile acid metabolism.

When Is It Safe to Proceed With Pancreaticoduodenectomy Without Biliary Decompression?

BACKGROUND

An absolute bilirubin level where preoperative biliary decompression (PBD) is indicated before pancreaticoduodenectomy has been elusive. Our goal was to identify a total bilirubin level whereby biliary decompression provides clear benefit, despite associated expenses and potential complications.

MATERIALS AND METHODS

We reviewed a prospectively collected database of patients undergoing pancreaticoduodenectomy at the Vidant Medical Center between 2007 and 2016. Patients were arbitrarily subdivided into 3 groups based on presenting bilirubin level (≤10 mg/dL, 10.1-14.9 mg/dL, and ≥15 mg/dL) to determine the presence of overall complications, severe complications (Clavien-Dindo classification ≥3), prolonged length of stay (>1 SD), readmissions, or mortality.

RESULTS

Common bile duct stenting independently predicted a higher incidence of complications in patients presenting with bilirubin ≤10 mg/dL (P = .03) vs. those patients going directly to surgery. No differences were observed for patients with bilirubin between 10.1 mg/dL and 14.9 mg/dL. Biliary decompression in patients with bilirubin ≥15 mg/dL independently predicted fewer overall (73.8% vs. 100%, P = .0082) and less severe complications (14.3% vs. 44.5%, P = .03) and lower readmission rates (15.8% vs. 55.6%, P = .03) vs. those going directly to surgery. Patients not undergoing biliary decompression underwent pancreaticoduodenectomy sooner than those decompressed (4.7 days vs. 17.2 days, P = .01).

DISCUSSION

All patients presenting with bilirubin ≥15 mg/dL should undergo PBD, while those with bilirubin ≤10 mg/dL should forego stent placement to avoid stent-related complications. The decision to stent between 10.1 and 14.9 mg/dL should be made on a case-by-case basis keeping in mind timeliness to definitive cancer treatment.

Bile canaliculi contract autonomously by releasing calcium into hepatocytes via mechanosensitive calcium channel

Drug-induced hepatocellular cholestasis leads to altered bile flow. Bile is propelled along the bile canaliculi (BC) by actomyosin contractility, triggered by increased intracellular calcium (Ca²⁺). However, the source of increased intracellular Ca²⁺ and its relationship to transporter activity remains elusive. We identify the source of the intracellular Ca²⁺ involved in triggering BC contractions, and we elucidate how biliary pressure regulates Ca²⁺ homeostasis and associated BC contractions. Primary rat hepatocytes were cultured in collagen sandwich. Intra-canalicular Ca²⁺ was measured with fluo-8; and intra-cellular Ca²⁺ was measured with GCaMP. Pharmacological modulators of canonical Ca²⁺-channels were used to study the Ca²⁺-mediated regulation of BC contraction. BC contraction correlates with cyclic transfer of Ca²⁺ from BC to adjacent hepatocytes, and not with endoplasmic reticulum Ca²⁺. A mechanosensitive Ca²⁺ channel (MCC), Piezo-1, is preferentially localized at BC membranes. The Piezo-1 inhibitor GsMTx-4 blocks the Ca²⁺ transfer, resulting in cholestatic generation of BC-derived vesicles whereas Piezo-1 hyper-activation by Yoda1 increases the frequency of Ca²⁺ transfer and BC contraction cycles. Yoda1 can recover normal BC contractility in drug-induced hepatocellular cholestasis, supporting that Piezo-1 regulates BC contraction cycles. Finally, we show that hyper-activating Piezo-1 can be exploited to normalize bile flow in drug-induced hepatocellular cholestasis.

Bile Acid Signaling in Neurodegenerative and Neurological Disorders

Bile acids are commonly known as digestive agents for lipids. The mechanisms of bile acids in the gastrointestinal track during normal physiological conditions as well as hepatic and cholestatic diseases have been well studied. Bile acids additionally serve as ligands for signaling molecules such as nuclear receptor Farnesoid X receptor and membrane-bound receptors, Takeda G-protein-coupled bile acid receptor and sphingosine-1-phosphate receptor 2. Recent studies have shown that bile acid signaling may also have a prevalent role in the central nervous system. Some bile acids, such as tauroursodeoxycholic acid and ursodeoxycholic acid, have shown neuroprotective potential in experimental animal models and clinical studies of many neurological conditions. Alterations in bile acid metabolism have been discovered as potential biomarkers for prognosis tools as well as the expression of various bile acid receptors in multiple neurological ailments. This review explores the findings of recent studies highlighting bile acid-mediated therapies and bile acid-mediated signaling and the roles they play in neurodegenerative and neurological diseases.

Bacteriobilia resistance to antibiotic prophylaxis increases morbidity after pancreaticoduodenectomy: a monocentric retrospective study of 128 patients

Several studies attempted to determine whether there is a relationship between the use of preoperative biliary drainage and morbidity after pancreaticoduodenectomy (PD). We retrospectively evaluated post-PD outcome in patients with and without preoperative biliary drainage and the role of bacteriobilia and antibiotic prophylaxis in post-operative complications. Data relating to the PDs performed at the Hepato-Bilio-Pancreatic Surgical Department of Treviso Hospital between 2010 and 2017 were retrospectively evaluated. Morbidity and intra-hospital mortality related to preoperative biliary stent were the primary outcomes. Between 2010 and 2017, 128 patients (mean age 68 years) underwent PD; 72 were treated with early surgery (ES) and 56 underwent preoperative biliary drainage (PBD). Overall morbidity was 50% in the ES cohort and 43% in the PBD (ns, p = 0.43). In the PBD group, bacteriobilia was found in the 100% of the bile cultures (48; 8 unavailable). The microbiota was represented by: Klebsiella spp (48%), Enterococcus spp (29%), E. coli (27%) and Candida spp (21%). In 52% of cases, at least one of the isolated bacteria was resistant to the perioperative antibiotic prophylaxis (69% of cases Amoxicillin-Clavulanic Ac.). The majority of postoperative surgical complications occurred in patients with prophylaxis-resistant bacteriobilia (68% vs 39%; p = 0.04). Antibiotic resistance is a determining factor in morbidity after PD. We therefore propose to pay particular attention to the preoperative prophylaxis, diversifying it between drained and non-drained patients. In fact, in the former, appropriate broad spectrum preoperative antibiotic coverage is strongly suggested.

The impact of preoperative biliary stenting in pancreatic cancer: A case-matched study from the German nationwide pancreatic surgery registry (DGAV StuDoQ|Pancreas)

BACKGROUND/OBJECTIVE

The impact of preoperative biliary stenting (PBS) before pancreatoduodenectomy (PD) for pancreatic ductal adenocarcinoma (PDAC) is controversial.

METHODS

Patients undergoing PD with or without PBS for PDAC were identified from the German DGAV-StuDoQlPancreas registry. The impact of PBS on perioperative complications was analyzed.

RESULTS

1133 patients undergoing PD for PDAC were identified from the registry. After matching, 480 PBS patients vs. 480 patients without PBS were analyzed. Postoperative complications Clavien-Dindo classification (CDC) grade IIIa-IVb were higher in PBS patients (PBS 27% vs. no PBS 22%, p = 0.027). 320 PBS patients (66%) had no history of jaundice. In these patients, PBS was associated with higher morbidity. In contrast, PBS was not associated with higher complication rates in patients with history of jaundice. Serum bilirubin levels of 15 mg/dl and higher lead to more CDC IIIa-IVb (24% vs. 28%, p = 0.053) and higher mortality (3% vs. 7%, p < 0.001). PBS in patients with serum bilirubin levels of >15 mg/dl increased CDC IIa-IVb complications (21% vs. 50%, p = 0.001), mortality was equivalent.

CONCLUSION

Most PBS procedures were performed in patients with no history of jaundice and increased morbidity. Serum bilirubin levels >15 mg/dl lead to higher morbidity and mortality. PBS correlated with higher complication rates in these patients.

Alisma orientale extract exerts the reversing cholestasis effect by activation of farnesoid X receptor

BACKGROUND

Cholestasis is a clinical syndrome of liver damage that is caused by accumulation of bile acids in the liver and systemic circulation. Farnesoid X receptor (FXR) can regulate synthesis, metabolism, and excretion of bile acids. The rhizomes of Alisma orientale is a well-known traditional Chinese medicine to treat edema, obesity, gonorrhea, leukorrhea, diarrhea, hyperlipidemia, and diabetes in China.

HYPOTHESIS/PURPOSE

We hypothesized Alisma orientale extract (AOE) to exert hepatoprotective effect against α-naphthylisothiocyanate (ANIT) induced cholestasis in rat. We aimed to investigate the mechanism of AOE.

STUDY DESIGN

Male Sprague Dawley rats with intrahepatic cholestasis induced by ANIT were treated with AOE (150, 300, or 600 mg/kg). Rats receiving vehicle (0.5% CMC-Na) served as control.

METHODS

48 h after ANIT administration, rats were sacrificed. Blood was collected to obtain serum and livers were removed for histopathology and protein preparation. Biochemical indicators in serum were determined using commercial kits and triterpenoids were determined by liquid chromatography tandem Qtrap mass spectrometry. Proteomics was analyzed by liquid chromatography tandem ion-trap mass spectrometry. The differently expressed proteins were analyzed via the network database and verified by western blotting. The interaction between triterpenoids and FXR were evaluated by luciferase assay and molecular docking.

RESULTS

AOE treatment significantly decreased the serum AST, ALT, TBIL, and intrahepatic TBA and improved the liver pathologic change induced by ANIT. Proteomics analysis indicated that AOE regulated proteins related to bile acid homeostasis via activating farnesoid X receptor (FXR) signaling pathway. Luciferase assay and molecular docking results indicated that triterpenoids could activate FXR, which resulting in ameliorative accumulation of bile acids in the liver by increase of metabolism and transportation for bile acids, and decrease of synthesis for bile acids.

CONCLUSION

AOE protected against rat liver injury and cholestasis induced by ANIT by activation of farnesoid X receptor, suggesting that A. orientale could be regarded as a potential hepatoprotective drug.

Synthesis, physicochemical properties, and biological activity of bile acids 3-glucuronides: Novel insights into bile acid signalling and detoxification

Glucuronidation is considered an important detoxification pathway of bile acids especially in cholestatic conditions. Glucuronides are less toxic than the parent free forms and are more easily excreted in urine. However, the pathophysiological significance of bile acid glucuronidation is still controversial and debated among the scientific community. Progress in this field has been strongly limited by the lack of appropriate methods for the preparation of pure glucuronides in the amount needed for biological and pharmacological studies. In this work, we have developed a new synthesis of bile acid C3-glucuronides enabling the convenient preparation of gram-scale quantities. The synthesized compounds have been characterized in terms of physicochemical properties and abilities to modulate key nuclear receptors including the farnesoid X receptor (FXR). In particular, we found that C3-glucuronides of chenodeoxycholic acid and lithocholic acid, respectively the most abundant and potentially cytotoxic species formed in patients affected by cholestasis, behave as FXR agonists and positively regulate the gene expression of transporter proteins, the function of which is critical in human conditions related to imbalances of bile acid homeostasis.

Activation of PPARα decreases bile acids in livers of female mice while maintaining bile flow and biliary bile acid excretion

Fibrates are hypolipidemic drugs that act as activators of peroxisome proliferator-activated receptor α (PPARα). In both humans and rodents, females were reported to be less responsive to fibrates than males. Previous studies on fibrates and PPARα usually involved male mice, but little has been done in females. The present study aimed to provide the first comprehensive analysis of the effects of clofibrate (CLOF) and PPARα on bile acid (BA) homeostasis in female mice. Study in WT male mice showed that a 4-day CLOF treatment increased liver weight, bile flow, and biliary BA excretion, but decreased total BAs in both serum and liver. In contrast, WT female mice were less susceptible to these CLOF-mediated responses observed in males. In WT female mice, CLOF decreased total BAs in the liver, but had little effect on the mRNAs of hepatic BA-related genes. Next, a comparative analysis between WT and PPARα-null female mice showed that lack of PPARα in female mice decreased total BAs in serum, but had little effect on total BAs in liver or bile. However, lack of PPARα in female mice increased mRNAs of BA synthetic enzymes (Cyp7a1, Cyp8b1, Cyp27a1, and Cyp7b1) and transporters (Ntcp, Oatp1a1, Oatp1b2, and Mrp3). Furthermore, the increase of Cyp7a1 in PPARα-null female mice was associated with an increase in liver Fxr-Shp-Lrh-1 signaling. In conclusion, female mice are resistant to CLOF-mediated effects on BA metabolism observed in males, which could be attributed to PPARα-mediated suppression in females on genes involved in BA synthesis and transport.

Effect of Disease Pathologies on Transporter Expression and Function

Transporters are important determinants of drug absorption, distribution, and excretion. The clinical relevance of drug transporters in drug disposition and toxicology depends on their localization in liver, kidney, and brain. There has been growing evidence regarding the importance of disease status on alterations in metabolizing enzymes and transporter proteins. This review focuses on uptake and efflux transporter proteins in liver, kidney, and brain and discusses mechanisms of altered transporter expression and function secondary to disease.

Value of preoperative biliary drainage on postoperative outcome after pancreaticoduodenectomy: A case-control study

BACKGROUND/OBJECTIVE

The potential benefit of preoperative biliary drainage (PBD) on postoperative outcomes remains controversial. The aim of this study was to elucidate surgical outcomes of pancreaticoduodenectomy (PD) in patients with PBD and to show the impact of bilirubin level.

METHODS

We retrospectively studied all patients who underwent PD in our center between January 2003 and June 2015. Patients were divided into: Group A (PBD) and Group B (no PBD). The primary outcome was the rate of postoperative complication.

RESULTS

A total of 588 cases underwent PD. Group A included 314 (53.4%) patients while Group B included 274 (46.6%) patients. The overall incidence of complications and its severity were higher in Group A (p = 0.03 and p = 0.02). There was significant difference in the incidence of postoperative pancreatic fistula (p = 0.002), delayed gastric emptying (p = 0.005), biliary leakage (p = 0.04), abdominal collection (p = 0.04), and wound infection (p = 0.04) in Group A. The mean length of hospital stay was significantly longer in Group A than in Group B (12.86 ± 7.65 days vs. 11.05 ± 7.98 days, p = 0.01). No significant impact of preoperative bilirubin level on surgical outcome was detected.

CONCLUSION

PBD before PD was associated with major postoperative complications and stent-related complications.

Endoscopic versus Percutaneous Biliary Drainage in Palliation of Advanced Malignant Hilar Obstruction: A Meta-Analysis and Systematic Review

Background. Palliation in advanced unresectable hilar malignancies can be achieved by endoscopic (EBD) or percutaneous transhepatic biliary drainage (PTBD). It is unclear if one approach is superior to the other in this group of patients. Aims. Compare clinical outcomes of EBD versus PTBD. Methods. (i) Study Selection Criterion. Studies using PTBD and EBD for palliation of advanced unresectable hilar malignancies. (ii) Data Collection and Extraction. Articles were searched in Medline, PubMed, and Ovid journals. (iii) Statistical Method. Fixed and random effects models were used to calculate the pooled proportions. Results. Initial search identified 786 reference articles, in which 62 articles were selected and reviewed. Data was extracted from nine studies (N = 546) that met the inclusion criterion. The pooled odds ratio for successful biliary drainage in PTBD versus EBD was 2.53 (95% CI = 1.57 to 4.08). Odds ratio for overall adverse effects in PTBD versus EBD groups was 0.81 (95% CI = 0.52 to 1.26). Odds ratio for 30-day mortality rate in PTBD group versus EBD group was 0.84 (95% CI = 0.37 to 1.91). Conclusions. In patients with advanced unresectable hilar malignancies, palliation with PTBD seems to be superior to EBD. PTBD is comparable to EBD in regard to overall adverse effects and 30-day mortality.

Bile deficiency induces changes in intestinal glucose absorption in mice

BACKGROUND

Biliary tract obstruction is a common clinical problem. In this study, we attempted to understand the change in intestinal glucose absorption after biliary tract obstruction.

METHODS

Experimental models of murine biliary duct ligation and external biliary drainage were established. Murine intestinal mucosal glucose absorption was examined with Ussing chambers according to the increase in the short-circuit current in vitro and blood glucose measurement after oral glucose in vivo. The protein expression of the sodium-glucose cotransporter (SGLT1) and the facilitated glucose transporter, member 2 (GLUT2) was analyzed by Western blot and immunohistochemistry.

RESULTS

The results from Ussing chamber experiments showed that duodenal mucosal glucose absorption levels were significantly higher in biliary duct ligation and biliary drainage mice than those in normal control mice at 1 and 2 weeks after the operation. Gastrointestinal bile acid administration almost reversed the elevated duodenal mucosal glucose absorption to the normal level in biliary drainage mice. The results from the experiments in vivo further confirmed that the glucose absorption increased in biliary duct ligation and biliary drainage mice. The protein expression levels of SGLT1 in the duodenal mucosae of both biliary duct ligation and biliary drainage mice were markedly higher than those in control mice, and the protein expression of GLUT2 was not significantly altered, compared with control mice.

CONCLUSION

Bile deficiency in the intestine upregulates the expression of intestinal mucosal SGLT1 and enhances intestinal mucosal glucose absorption capacity, which contributes to the understanding of intestinal physiologic function for patients with biliary duct obstruction and external biliary drainage.

Efficacy of preoperative biliary drainage in malignant obstructive jaundice: a meta-analysis and systematic review

BACKGROUND

In patients requiring surgical resection for malignant biliary jaundice, it is unclear if preoperative biliary drainage (PBD) would improve mortality and morbidity by restoration of biliary flow prior to operation. This is a meta-analysis to pool the evidence and assess the utility of PBD in patients with malignant obstructive jaundice. The primary outcome is comparing mortality outcomes in patients with malignant obstructive jaundice undergoing direct surgery (DS) versus PBD. The secondary outcomes include major adverse events and length of hospital stay in both the groups.

METHODS

Studies using PBD in patients with malignant obstructive jaundice were included in this study. For the data collection and extraction, articles were searched in MEDLINE, PubMed, Embase, Cochrane Central Register of Controlled Trials & Database of Systematic Reviews, etc. Pooled proportions were calculated using both Mantel-Haenszel method (fixed effects model) and DerSimonian-Laird method (random effects model).

RESULTS

Initial search identified 2230 reference articles, of which 204 were selected and reviewed. Twenty-six studies (N = 3532) for PBD in malignant obstructive jaundice which met the inclusion criteria were included in this analysis. The odds ratio for mortality in PBD group versus DS group was 0.96 (95 % CI = 0.71 to 1.29). Pooled number of major adverse effects was lower in the PBD group at 10.40 (95 % CI = 9.96 to 10.83) compared to 15.56 (95 % CI = 15.06 to 16.05) in the DS group. Subgroup analysis comparing internal PBD to DS group showed lower odds for major adverse events (odds ratio, 0.48 with 95 % CI = 0.32 to 0.74).

CONCLUSIONS

In patients with malignant biliary jaundice requiring surgery, PBD group had significantly less major adverse effects than DS group. Length of hospital stay and mortality rate were comparable in both the groups.

Role of enterohepatic recirculation in drug disposition: cooperation and complications

Enterohepatic recirculation (EHC) concerns many physiological processes and notably affects pharmacokinetic parameters such as plasma half-life and AUC as well as estimates of bioavailability of drugs. Also, EHC plays a detrimental role as the compounds/drugs are allowed to recycle. An in-depth comprehension of this phenomenon and its consequences on the pharmacological effects of affected drugs is important and decisive in the design and development of new candidate drugs. EHC of a compound/drug occurs by biliary excretion and intestinal reabsorption, sometimes with hepatic conjugation and intestinal deconjugation. EHC leads to prolonged elimination half-life of the drugs, altered pharmacokinetics and pharmacodynamics. Study of the EHC of any drug is complicated due to unavailability of the apposite model, sophisticated procedures and ethical concerns. Different in vitro and in vivo methods for studies in experimental animals and humans have been devised, each having its own merits and demerits. Involvement of the different transporters in biliary excretion, intra- and inter-species, pathological and biochemical variabilities obscure the study of the phenomenon. Modeling of drugs undergoing EHC has always been intricate and exigent models have been exploited to interpret the pharmacokinetic profiles of drugs witnessing multiple peaks due to EHC. Here, we critically appraise the mechanisms of bile formation, factors affecting biliary drug elimination, methods to estimate biliary excretion of drugs, EHC, multiple peak phenomenon and its modeling.

Isoflavones and phytosterols contained in Xuezhikang capsules modulate cholesterol homeostasis in high-fat diet mice

AIM

Xuezhikang (XZK), an extract of red yeast rice, has been widely used in traditional Chinese medicine to treat cardiovascular disease. Three fractions F1, F2 and F3 (primarily containing isoflavones, monacolins or phytosterols, respectively) are extracted from Xuezhikang capsules. In this study we evaluated the lipid-lowering effects of these fractions and explored the potential mechanisms of actions.

METHODS

Mice treated with a high-fat diet (HFD) were orally administered lovastatin (10 mg·kg(-1)·d(-1)), XZK (1200 mg·kg(-1)·d(-1)), F1 (27.5 mg·kg(-1)·d(-1)), F2 (11.3 mg·kg(-1)·d(-1)) or F3 (35 mg·kg(-1)·d(-1)) for 10 weeks. Lipids were measured using commercial enzymatic kits, and the mRNA and protein levels of genes involved in cholesterol and bile acid homeostasis were evaluated using qRT-PCR and Western blot analysis, respectively.

RESULTS

XZK increased the fecal excretion of lipids and bile acids, reduced serum TC, TG and LDL-C levels by 40%, 55% and 46%, respectively, and increased serum HDL-C by 31%. Administration of F1 repressed serum TC and TG by 24% and 52%, respectively, and elevated hepatic synthesis of CYP7A1. It also increased hepatic elimination of bile acids in the fecal excretions by 79% through upregulating BSEP and downregulating NTCP. Administration of F3 decreased serum TC, TG and LDL-C levels by 33%, 29% and 39%, respectively, and increased serum HDL-C by 28%, significantly reduced intestinal absorption of cholesterol by inhibiting the transcription of NPC1L1, and elevated excretion of TC, FC and CE by 96%, 72% and 101%, respectively. Administration of F2 showed pharmacological effects similar to those of lovastatin.

CONCLUSION

Isoflavones and phytosterols in XZK exert cholesterol-lowering effects in HFD mice through mechanisms that differ from those of lovastatin. Isoflavones and phytosterols act in a complimentary manner: through enhancing the elimination of bile acids and reducing intestinal cholesterol absorption, respectively.

Metabolomics changes in a rat model of obstructive jaundice: mapping to metabolism of amino acids, carbohydrates and lipids as well as oxidative stress

The study examined the global metabolic and some biochemical changes in rats with cholestasis induced by bile duct ligation (BDL). Serum samples were collected in male Wistar rats with BDL (n = 8) and sham surgery (n = 8) at day 3 after surgery for metabolomics analysis using a combination of reversed phase chromatography and hydrophilic interaction chromatography (HILIC) and quadrupole-time-of-flight mass spectrometry (Q-TOF MS). The serum levels of malondialdehyde (MDA), total antioxidative capacity (T-AOC), glutathione (GSH) and glutathione disulfide (GSSG), the activities of superoxide dismutase (SOD) and glutathion peroxidase (GSH-Px) were measured to estimate the oxidative stress state. Key changes after BDL included increased levels of l-phenylalanine, l-glutamate, l-tyrosine, kynurenine, l-lactic acid, LysoPC^c (14:0), glycine and succinic acid and decreased levels of l-valine, PC^b (19:0/0:0), taurine, palmitic acid, l-isoleucine and citric acid metabolism products. And treatment with BDL significantly decreased the levels of GSH, T-AOC as well as SOD, GSH-Px activities, and upregulated MDA levels. The changes could be mapped to metabolism of amino acids and lipids, Krebs cycle and glycolysis, as well as increased oxidative stress and decreased antioxidant capability. Our study indicated that BDL induces major changes in the metabolism of all 3 major energy substances, as well as oxidative stress.

Urinary bile acids as biomarkers for liver diseases I. Stability of the baseline profile in healthy subjects

The role of bile acids (BAs) as biomarkers for liver injury has been proposed for decades. However, the large inter- and intra-individual variability of the BA profile has prevented its clinical application. To this end, we investigated the effect of covariates such as food, gender, age, BMI, and moderate alcohol consumption on the BA profile in healthy human subjects. The BA profile was characterized by the calculation of indices that describe the composition, sulfation, and amidation of total and individual BAs. Both inter- and intra-individual variabilities of BA indices were low in serum and even lower in urine compared with those of absolute concentrations of BAs. Serum BA concentrations increased with consumption of food, whereas urinary BA concentrations were mildly affected by food. Gender differences in the urinary and serum BA profile were minimal. The serum and urinary BA profiles were also not affected by age. BMI showed minimal effect on the urine and serum BA profile. Moderate alcohol consumption did not have a significant effect on the BA profile in both urine and serum. When the effect of the type of alcohol was studied, the results indicate that moderate drinking of beer does not affect BA concentrations and has minimal effect on BA indices, whereas moderate wine consumption slightly increases BA concentrations without affecting the BA indices. In summary, urinary BA indices showed lower variability and higher stability than absolute BA concentrations in serum and showed minimal changes to covariate effects suggesting their utility as biomarkers in clinic.

Meta-analysis of randomized clinical trials on safety and efficacy of biliary drainage before surgery for obstructive jaundice

BACKGROUND

This meta-analysis aimed to investigate whether preoperative biliary drainage (PBD) is beneficial to patients with obstructive jaundice.

METHODS

Data from randomized clinical trials related to safety and effectiveness of PBD versus no PBD were extracted by two independent reviewers. Risk ratios, rate ratios or mean differences were calculated with 95 per cent confidence intervals (c.i.), based on intention-to-treat analysis, whenever possible.

RESULTS

Six trials (four using percutaneous transhepatic biliary drainage and two using endoscopic sphincterotomy) including 520 patients with malignant or benign obstructive jaundice comparing PBD (265 patients) with no PBD (255) were included in this review. All trials had a high risk of bias. There was no significant difference in mortality (risk ratio 1.12, 95 per cent c.i. 0.73 to 1.71; P = 0.60) between the two groups. Overall serious morbidity (grade III or IV, Clavien-Dindo classification) was higher in the PBD group (599 complications per 1000 patients) than in the direct surgery group (361 complications per 1000 patients) (rate ratio 1.66, 95 per cent c.i. 1.28 to 2.16; P < 0.001). Quality of life was not reported in any of the trials. There was no significant difference in length of hospital stay between the two groups: mean difference 4.87 (95 per cent c.i. -1.28 to 11.02) days (P = 0.12).

CONCLUSION

PBD in patients undergoing surgery for obstructive jaundice is associated with similar mortality but increased serious morbidity compared with no PBD. Therefore, PBD should not be used routinely.

Analysis of the metabolic properties of maintenance hemodialysis patients with glucose-added dialysis based on high performance liquid chromatography quadrupole time-of-flight mass spectrometry

The purpose of this study was to compare the metabolic properties of maintenance hemodialysis patients treated with glucose-containing and glucose-free dialysate using metabonomics. Pre- and post-dialysis serum samples from group G (-) using glucose-free dialysate, and group G (+) using glucose-added dialysate (glucose levels were 5.5 mmol/L) were analyzed and tested with high performance liquid chromatography quadrupole time-of-flight mass spectrometry. Orthogonal signal correction-partial least squares discriminate analysis revealed a significant difference in the post-dialysis metabolic properties between samples from the G (-) and G (+) groups, and concentrations of leucine and dihydroxyprostaglandin F2α were higher in the G (+) group than in the G (-) group. However, markers of reactive lipid mobilization and amino acid release, such as bile acids, aspartate, and valine, were lower in the G (+) group than in the G (-) group. There were no significant differences in excitatory neurotransmitters aspartate and phosphorylated anandamide. Use of liquid chromatography-tandem mass spectrometry metabonomics indicated that using glucose-added dialysate was superior to glucose-free dialysate in the protection of the central nervous system of maintenance hemodialysis patients, but had potential risks in stimulating oxidative stress.

Nuclear receptors and endobiotics glucuronidation: the good, the bad, and the UGT

The recent progresses in molecular biology and pharmacology approaches allowed the characterization of a series of nuclear receptors (NRs) as efficient regulators of uridine diphosphate glucuronosyltransferase (UGT) genes activity. These regulatory processes ensure an optimized UGT expression in response to specific endo- and/or exogenous stimuli. Many of these NRs are activated by endobiotics that also are substrates for UGTs. Thus, by activating their receptors, these endogenous substances control their own conjugation, leading to the concept that glucuronidation is an important part of feed-forward/feedback mechanisms by which bioactive molecules control their own concentrations. On the other hand, numerous studies have established the pharmacological relevance of NR-UGT regulatory pathways in the response to therapeutic ligands. The present review article aims at providing a comprehensive view of the physiological and pharmacological importance of the NR regulation of the expression and activity of endobiotics-conjugating UGT enzymes. Selected examples will illustrate how the organism profits from the feed-forward/feedback mechanisms involving NR-UGT pathways, but also how such regulatory processes are involved in the initiation and/or progression of several pathological situations. Finally, we will discuss how the present pharmacopeia involves NR-dependent regulation of endobiotics glucuronidation, and whether the unexploited NR-UGT axes could serve as pharmacological targets for novel therapeutics to restore endobiotics homeostasis.

Profiling serum bile acid glucuronides in humans: gender divergences, genetic determinants, and response to fenofibrate

Glucuronidation, catalyzed by UDP-glucuronosyltransferase (UGT) enzymes detoxifies cholestatic bile acids (BAs). We aimed at i) characterizing the circulating BA-glucuronide (-G) pool composition in humans, ii) evaluating how sex and UGT polymorphisms influence this composition, and iii) analyzing the effects of lipid-lowering drug fenofibrate on the circulating BA-G profile in 300 volunteers and 5 cholestatic patients. Eleven BA-Gs were determined in pre- and post-fenofibrate samples. Men exhibited higher BA-G concentrations, and various genotype/BA-G associations were discovered in relevant UGT genes. The chenodeoxycholic acid-3G concentration was associated with the UGT2B7 802C>T polymorphism. Glucuronidation assays confirmed the predominant role of UGT2B7 and UGT1A4 in CDCA-3G formation. Fenofibrate exposure increased the serum levels of 5 BA-G species, including CDCA-3G, and up-regulated expression of UGT1A4, but not UGT2B7, in hepatic cells. This study demonstrates that fenofibrate stimulates BA glucuronidation in humans, and thus reduces bile acid toxicity in the liver.

Membrane vesicle ABC transporter assays for drug safety assessment

The use of plasma membrane vesicles that overexpress the bile salt export pump (BSEP) or multidrug resistance-associated protein 2, 3, or 4 (MRP2-4) with an in vitro vacuum filtration system offers a rapid and reliable means for screening drug candidates for their effects on transporter function in hepatocytes and thus their potential for causing drug-induced liver injury (DILI). Comparison of transporter activity in the presence and absence of ATP allows for determination of a specific assay window for each transporter. This window is used to determine the degree to which each test compound inhibits transporter activity. This assay battery is helpful for prioritizing and rank-ordering compounds within a chemical series with respect to each other and in the context of known inhibitors of transporter activity and/or liver injury. This model can be used to influence the drug development process at an early stage and provide rapid feedback regarding the selection of compounds for advancement to in vivo safety evaluations. A detailed protocol for the high-throughput assessment of ABC transporter function is provided, including specific recommendations for curve-fitting to help ensure consistent results.

Effects of 17α-ethynylestradiol-induced cholestasis on the pharmacokinetics of doxorubicin in rats: reduced biliary excretion and hepatic metabolism of doxorubicin

1. Since the prevalent hormonal combination therapy with estrogen analogues in cancer patients has frequency and possibility to induce the cholestasis, the frequent combination therapy with 17α-ethynylestradiol (EE, an oral contraceptive) and doxorubicin (an anticancer drug) might be monitored in aspect of efficacy and safety. Doxorubicin is mainly excreted into the bile via P-glycoprotein (P-gp) and multidrug resistance-associated protein 2 (Mrp2) in hepatobiliary route and metabolized via cytochrome P450 (CYP) 3A subfamily. Also the hepatic Mrp2 (not P-gp) and CYP3A subfamily levels were reduced in EE-induced cholestatic (EEC) rats. Thus, we herein report the pharmacokinetic changes of doxorubicin with respect to the changes in its biliary excretion and hepatic metabolism in EEC rats. 2. The pharmacokinetic study of doxorubicin after intravenous administration of its hydrochloride was conducted along with the investigation of bile flow rate and hepatobiliary excretion of doxorubicin in control and EEC rats. 3. The significantly greater AUC (58.7% increase) of doxorubicin in EEC rats was due to the slower CL (32.9% decrease). The slower CL was due to the reduction of hepatic biliary excretion (67.0% decrease) and hepatic CYP3A subfamily-mediated metabolism (21.9% decrease) of doxorubicin. These results might have broader implications to understand the altered pharmacokinetics and/or pharmacologic effects of doxorubicin via biliary excretion and hepatic metabolism in experimental and clinical estrogen-induced cholestasis.

Pre-operative biliary drainage for obstructive jaundice

BACKGROUND

Patients with obstructive jaundice have various pathophysiological changes that affect the liver, kidney, heart, and the immune system. There is considerable controversy as to whether temporary relief of biliary obstruction prior to major definitive surgery (pre-operative biliary drainage) is of any benefit to the patient.

OBJECTIVES

To assess the benefits and harms of pre-operative biliary drainage versus no pre-operative biliary drainage (direct surgery) in patients with obstructive jaundice (irrespective of a benign or malignant cause).

SEARCH METHODS

We searched the Cochrane Hepato-Biliary Group Controlled Trials Register, Cochrane Central Register of Controlled Clinical Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until February 2012.

SELECTION CRITERIA

We included all randomised clinical trials comparing biliary drainage followed by surgery versus direct surgery, performed for obstructive jaundice, irrespective of the sample size, language, and publication status.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trials for inclusion and extracted data. We calculated the risk ratio (RR), rate ratio (RaR), or mean difference (MD) with 95% confidence intervals (CI) based on the available patient analyses. We assessed the risk of bias (systematic overestimation of benefit or systematic underestimation of harm) with components of the Cochrane risk of bias tool. We assessed the risk of play of chance (random errors) with trial sequential analysis.

MAIN RESULTS

We included six trials with 520 patients comparing pre-operative biliary drainage (265 patients) versus no pre-operative biliary drainage (255 patients). Four trials used percutaneous transhepatic biliary drainage and two trials used endoscopic sphincterotomy and stenting as the method of pre-operative biliary drainage. The risk of bias was high in all trials. The proportion of patients with malignant obstruction varied between 60% and 100%. There was no significant difference in mortality (40/265, weighted proportion 14.9%) in the pre-operative biliary drainage group versus the direct surgery group (34/255, 13.3%) (RR 1.12; 95% CI 0.73 to 1.71; P = 0.60). The overall serious morbidity was higher in the pre-operative biliary drainage group (60 per 100 patients in the pre-operative biliary drainage group versus 26 per 100 patients in the direct surgery group) (RaR 1.66; 95% CI 1.28 to 2.16; P = 0.0002). The proportion of patients who developed serious morbidity was significantly higher in the pre-operative biliary drainage group (75/102, 73.5%) in the pre-operative biliary drainage group versus the direct surgery group (37/94, 37.4%) (P < 0.001). Quality of life was not reported in any of the trials. There was no significant difference in the length of hospital stay (2 trials, 271 patients; MD 4.87 days; 95% CI -1.28 to 11.02; P = 0.12) between the two groups. Trial sequential analysis showed that for mortality only a small proportion of the required information size had been obtained. There seemed to be no significant differences in the subgroup of trials assessing percutaneous compared to endoscopic drainage.

AUTHORS' CONCLUSIONS

There is currently not sufficient evidence to support or refute routine pre-operative biliary drainage for patients with obstructive jaundice. Pre-operative biliary drainage may increase the rate of serious adverse events. So, the safety of routine pre-operative biliary drainage has not been established. Pre-operative biliary drainage should not be used in patients undergoing surgery for obstructive jaundice outside randomised clinical trials.

Profile of serum bile acids in noncholestatic volunteers: gender-related differences in response to fenofibrate

Fenofibrate belongs to the group of hypolipidemic fibrates that act as activators of the peroxisome proliferator-activated receptor-α (PPARα), which is a regulator of bile acid synthesis, metabolism, and transport. The present study aimed at evaluating the effects of fenofibrate on the circulating bile acid profile in humans. A study population of 200 healthy individuals comprising both genders completed a 3-week intervention with fenofibrate, and 17 bile acid species were measured in serum samples drawn before and after fenofibrate treatment. Fenofibrate caused significant reductions in levels of chenodeoxycholic (CDCA) (-26.4%), ursodeoxycholic (UDCA) (-30.5%), lithocholic (LCA) (-18.4%), deoxycholic (DCA) (-22.3%), and hyodeoxycholic (HDCA) (-19.2%) acids. A gender-related difference was observed in the responses of various bile acids, and the total bile acid concentration was significantly reduced only in men (-18.6%), whereas it remained almost unchanged in women (+0.36%). This difference suggests that fenofibrate would be more efficient at reducing bile acid toxicity in men than in women in cholestatic liver diseases.

Pruritus of unknown origin and elevated total serum bile acid levels in patients without clinically apparent liver disease

BACKGROUND AND AIM

Generalized pruritus of unknown origin (PUO) is a highly distressing condition that is unrelated to any underlying dermatologic or systemic disorder (e.g. cholestasis). Little is known about the potential contribution of elevated total serum bile acid (TSBA) levels to PUO. Our aim in the present study was to investigate the role of elevated TSBA levels in patients with PUO and the efficacy of ursodeoxycholic acid (UDCA) and cholestyramine therapy.

METHODS

Retrospective study comprising 117 patients with chronic pruritic conditions (PUO, atopic disease, asteatotic eczema, latent cholestasis, etc.); 99 patients with available TSBA levels were included and compared with healthy controls.

RESULTS

Elevated TSBA levels were detected more frequently in patients with chronic pruritic diseases than in the control population (28.28% vs 6%; P<0.001) with significantly higher pathological absolute levels (mean 17.45±34.46 µmol/L vs 6.02±4.73 µmol/L; P=0.001). Patients with PUO (n=18) showed the second-highest prevalence of pathological bile acid level elevation (83.3%; control population 6%; P<0.001), after patients with subclinical cholestasis and presented with particularly high TSBA serum values (mean 37.79±53.38 µmol/L; P<0.001). Cholestyramine (n=9) and UDCA (n=8) therapy were both effective in lowering TSBA levels and lead to substantial improvement of pruritus in patients with elevated TSBA levels.

CONCLUSIONS

Total serum bile acid levels are elevated in a high proportion of patients with PUO. These results provide evidence of a potential involvement of subclinical cholestasis in the pathogenesis of PUO. We suggest that evaluation of TSBA levels should be included in the diagnostic work-up of patients with chronic unexplained pruritus.

ABCC2/Abcc2: a multispecific transporter with dominant excretory functions

ABCC2/Abcc2 (MRP2/Mrp2) is expressed at major physiological barriers, such as the canalicular membrane of liver cells, kidney proximal tubule epithelial cells, enterocytes of the small and large intestine, and syncytiotrophoblast of the placenta. ABCC2/Abcc2 always localizes in the apical membranes. Although ABCC2/Abcc2 transports a variety of amphiphilic anions that belong to different classes of molecules, such as endogenous compounds (e.g., bilirubin-glucuronides), drugs, toxic chemicals, nutraceuticals, and their conjugates, it displays a preference for phase II conjugates. Phenotypically, the most obvious consequence of mutations in ABCC2 that lead to Dubin-Johnson syndrome is conjugate hyperbilirubinemia. ABCC2/Abcc2 harbors multiple binding sites and displays complex transport kinetics.

Interference with bile salt export pump function is a susceptibility factor for human liver injury in drug development

The bile salt export pump (BSEP) is an efflux transporter, driving the elimination of endobiotic and xenobiotic substrates from hepatocytes into the bile. More specifically, it is responsible for the elimination of monovalent, conjugated bile salts, with little or no assistance from other apical transporters. Disruption of BSEP activity through genetic disorders is known to manifest in clinical liver injury such as progressive familial intrahepatic cholestasis type 2. Drug-induced disruption of BSEP is hypothesized to play a role in the development of liver injury for several marketed or withdrawn therapeutics. Unfortunately, preclinical animal models have been poor predictors of the liver injury associated with BSEP interference observed for humans, possibly because of interspecies differences in bile acid composition, differences in hepatobiliary transporter modulation or constitutive expression, as well as other mechanisms. Thus, a BSEP-mediated liver liability may go undetected until the later stages of drug development, such as during clinical trials or even postlicensing. In the absence of a relevant preclinical test system for BSEP-mediated liver injury, the toxicological relevance of available in vitro models to human health rely on the use of benchmark compounds with known clinical outcomes, such as marketed or withdrawn drugs. In this study, membrane vesicles harvested from BSEP-transfected insect cells were used to assess the activity of more than 200 benchmark compounds to thoroughly investigate the relationship between interference with BSEP function and liver injury. The data suggest a relatively strong association between the pharmacological interference with BSEP function and human hepatotoxicity. Although the most accurate translation of risk would incorporate pharmacological potency, pharmacokinetics, clearance mechanisms, tissue distribution, physicochemical properties, indication, and other drug attributes, the additional understanding of a compound's potency for BSEP interference should help to limit or avoid BSEP-related liver liabilities in humans that are not often detected by standard preclinical animal models.

Lipid-activated transcription factors control bile acid glucuronidation

Bile acids subserve important physiological functions in the control of cholesterol homeostasis. Indeed, hepatic bile acid synthesis and biliary excretion constitute the main route for cholesterol removal from the human body. On the other hand, bile acids serve as natural detergents for the intestinal absorption of dietary cholesterol. However, due to their detergent properties, bile acids are inherently cytotoxic, and their cellular level may be tightly controlled to avoid pathological situations such as cholestasis. Recent investigations have illustrated the crucial roles that a series of ligand-activated transcription factors has in the control of hepatic bile acids synthesis, transport and metabolism. Thus, the lipid-activated nuclear receptors, farnesoid X-receptor (FXR), liver X-receptor (LXR), pregnane X-receptor (PXR) and peroxisome proliferator-activated receptor alpha (PPAR alpha), modulate the expression and activity of genes controlling bile acid homeostasis in the liver. Several members of the UDP-glucuronosyltransferase (UGT) enzymes family are among the bile acid metabolizing enzymes regulated by these receptors. UGTs catalyze glucuronidation, a major phase II metabolic reaction, which converts hydrophobic bile acids into polar and urinary excretable metabolites. This article summarizes our recent observations on the regulation of bile acid conjugating UGTs upon pharmacological activation of lipid-activated receptors, with a particular interest for the role of PPAR alpha and LXRalpha in controlling human UGT1A3 expression.

Hepatobiliary phospholipid transporter ABCB4, MDR3 gene variants in a large cohort of Italian women with intrahepatic cholestasis of pregnancy

BACKGROUND

Intrahepatic cholestasis of pregnancy is a multifactorial disorder of pregnancy associated with a genetic background.

AIM

To evaluate the genetic contribution of ABCB4, MDR3 gene in the development of intrahepatic cholestasis of pregnancy in a large cohort of Italian subjects.

METHODS

This study represents an extension of a previous multicentre-prospective study including three Italian referral centres. In all, we enrolled 96 women at the 3rd trimester of pregnancy. Genomic DNA was extracted from peripheral venous blood leucocytes by standard procedures. Polymerase chain reaction was used to amplify exon 14, 15 and 16 of MDR3 gene.

RESULTS

We found 3 non-synonymous heterozygous mutations in exon 14 (E528D, R549H, G536A), 1 in exon 15 (R590Q) and 2 in exon 16 (R652G, T6671). MDR3 gene variants in exons 14, 15 and 16 occurred in 7/96 of pregnant mothers with intrahepatic cholestasis of pregnancy (7.2%), and in none of 96 pregnant controls matched for age and parity. All seven patients had normal gamma-glutamyl transpeptidase, normal bilirubin, but high levels of both alanine transferase and serum bile acids. One had cholesterol biliary lithiasis. The outcome of pregnancy was normal in four cases (with vaginal delivery), while there was one fetal distress.

CONCLUSIONS

MDR3 mutations are responsible for the development of intrahepatic cholestasis of pregnancy in only a small percentage of Italian women. Further genetic studies are warranted, however, to clarify the role of different mutations in intrahepatic cholestasis of pregnancy.