Treatment Of Cholestatic Liver Diseases Research Articles

Ursodeoxycholic acid and its unexpected application areas

Introduction. Ursodeoxycholic acid (UDCA) came into modern medicine in the 1970s as a potential solvent for small gallstones. But as early as the 1980s, there were clinical studies to improve biochemical indices when using UDCA in other liver diseases. These studies initiated a worldwide active study of the clinical possibilities and various therapeutic effects of UDCA in various diseases, including those beyond the liver. Today, worldwide, UDCA drugs are the lifelong basis for the treatment of primary sclerosing cholangitis (PSC). It is indicated for all types of hepatitis: infectious, toxic, drug-induced, autoimmune and others. It can be stated that the history of study and introduction of UDCA drugs in medicine is the history of the expansion of its application areas, which continues to this day. The purpose of the review is to present the results of the use of UDCA drugs outside the traditional circle of cholestatic liver diseases, the causes and possibilities of their use in other areas of medicine. Main principles. It has been shown that UDCA, originally designed for the treatment of cholestatic liver diseases, along with the known antioxidant, antifibrotic and immunomodulatory effects has a proven fundamental apoptosis regulatory effect. This allows it to have as a possible therapeutic target a whole range of extrahepatic diseases, such as gastrointestinal lesions (IBD, clostridi-osis, radiation and medical intestinal lesions, etc.), diseases of the cardiovascular system, neurodegenerative diseases (Alzheimer’s disease, Parkinson’s disease, ALS), prion diseases (Kuru, Creutzfeldt-Jakob disease) and a number of others. Conclusion. According to modern views, UDCA can be considered as a unique drug of universal cytoprotective action, the expansion of its therapeutic possibilities is promising and is subject to further multilateral study.

Probiotic Lactobacillus rhamnosus GG Prevents Liver Fibrosis Through Inhibiting Hepatic Bile Acid Synthesis and Enhancing Bile Acid Excretion in Mice.

Background and AimsCholestatic liver disease is characterized by gut dysbiosis and excessive toxic hepatic bile acids (BAs). Modification of gut microbiota and repression of BA synthesis are potential strategies for the treatment of cholestatic liver disease. The purpose of this study was to examine the effects and to understand the mechanisms of the probiotic Lactobacillus rhamnosus GG (LGG) on hepatic BA synthesis, liver injury, and fibrosis in bile duct ligation (BDL) and multidrug resistance protein 2 knockout (Mdr2−/−) mice.Approach and ResultsGlobal and intestine‐specific farnesoid X receptor (FXR) inhibitors were used to dissect the role of FXR. LGG treatment significantly attenuated liver inflammation, injury, and fibrosis with a significant reduction of hepatic BAs in BDL mice. Hepatic concentration of taurine‐β‐muricholic acid (T‐βMCA), an FXR antagonist, was markedly increased in BDL mice and reduced in LGG‐treated mice, while chenodeoxycholic acid, an FXR agonist, was decreased in BDL mice and normalized in LGG‐treated mice. LGG treatment significantly increased the expression of serum and ileum fibroblast growth factor 15 (FGF‐15) and subsequently reduced hepatic cholesterol 7α‐hydroxylase and BA synthesis in BDL and Mdr2−/− mice. At the molecular level, these changes were reversed by global and intestine‐specific FXR inhibitors in BDL mice. In addition, LGG treatment altered gut microbiota, which was associated with increased BA deconjugation and increased fecal and urine BA excretion in both BDL and Mdr2−/− mice. In vitro studies showed that LGG suppressed the inhibitory effect of T‐βMCA on FXR and FGF‐19 expression in Caco‐2 cells.ConclusionLGG supplementation decreases hepatic BA by increasing intestinal FXR–FGF‐15 signaling pathway–mediated suppression of BA de novo synthesis and enhances BA excretion, which prevents excessive BA‐induced liver injury and fibrosis in mice.

Ursodeoxycholic acid attenuates the expression of proinflammatory cytokines in periodontal cells.

BackgroundUrsodeoxycholic acid (UDCA) is one of the first‐line therapeutic medications used in treatment of cholestatic liver disease. Considering that periodontitis is epidemiologically linked to liver diseases, the question arises weather UDCA holds anti‐inflammatory properties on periodontal health. Herein, we provide information that support anti‐inflammatory effects of UDCA on three different periodontium‐related cell types.MethodsGingival fibroblasts and the oral human squamous carcinoma cell line HSC‐2 were exposed to interleukin (IL)1β and tumor necrosis factor (TNF)α with and without UDCA. Murine RAW 264.7 macrophages were incubated with sterile‐filtered human saliva also in the presence of UDCA. The expression of inflammatory cytokines was measured by reverse transcription‐polymerase chain reaction. Immunoassay was applied to detect the production of IL6. Immunostaining was performed for the p65 subunit to further support the anti‐inflammatory role of UDCA.ResultsWe report here that UDCA significantly reduced the IL1β and TNFα‐induced expression of IL1, IL6, and IL8 in gingival fibroblasts and the HSC‐2 cell line. In RAW 264.7 macrophages, UDCA attenuated the expression of IL1α, IL1β, and IL6 that was increased by saliva. Immunoassay confirmed the capacity of UDCA to reduce inflammation‐induced production of IL6 in gingival fibroblasts, HSC‐2 and RAW 264.7 cells. Immunostaining revealed the blocking of nuclear translocation of p65 in gingival fibroblasts.ConclusionsTaken together, UDCA can attenuate the provoked expression of inflammatory cytokines in oral fibroblasts, oral human squamous carcinoma cells and macrophages in vitro. These data support the hypothesis that patients with cholestatic liver disease might benefit from UDCA with respect to periodontal health.

Nerve growth factor induced farnesoid X receptor upregulation modulates autophagy flux and protects hepatocytes in cholestatic livers

Upregulation of nerve growth factor (NGF) in parenchymal hepatocytes has been shown to exert hepatoprotective function during cholestatic liver injury. However, the modulatory role of NGF in regulation of liver autophagy remains unclear. This study aimed to scrutinize the regulatory role of NGF in hepatic expression of farnesoid X receptor (FXR), a bile acid (BA)-activated nuclear receptor, and to determine its cytoprotective effect on BA-induced autophagy and cytotoxicity. Livers of human hepatolithiasis and bile duct ligation (BDL)-induced mouse cholestasis were used for histopathological and molecular detection. The regulatory roles of NGF in autophagy flux and FXR expression, as well as its hepatoprotection against BA cytotoxicity were examined in cultured hepatocytes. FXR downregulation in human hepatolithiasis livers showed positive correlation with hepatic NGF levels. NGF administration upregulated hepatic FXR levels, while neutralization of NGF decreased FXR expression in BDL-induced cholestatic mouse livers. In vitro studies demonstrated that NGF upregulated FXR expression, increased cellular LC3 levels, and exerted hepatoprotective effect in cultured primary rat hepatocytes. Conversely, autophagy inhibition abrogated NGF-driven cytoprotection under BA exposure, suggesting involvement of NGF-modulated auophagy flux. Although FXR agonistic GW4064 stimulation did not affect auophagic LC3 levels, FXR activity inhibition significantly potentiated BA-induced cytotoxicity and increased cellular p62/SQSTM1 and Rab7 protein in SK-Hep1 hepatocytes. Moreover, FXR gene silencing abolished the protective effect of NGF under BA exposure. These findings support that NGF modulates autophagy flux via FXR upregulation and protects hepatocytes against BA-induced cytotoxicity. NGF/FXR axis is a novel therapeutic target for treatment of cholestatic liver diseases.

Picroside II protects against cholestatic liver injury possibly through activation of farnesoid X receptor

BackgroudCholestasis, accompanied by the accumulation of bile acids in body, may ultimately cause liver failure and cirrhosis. There have been limited therapies for cholesteric disorders. Therefore, development of appropriate therapeutic drugs for cholestasis is required. Picroside II is a bioactive component isolated from Picrorhiza scrophulariiflora Pennell, its mechanistic contributions to the anti-cholestasis effect have not been fully elucidated, especially the role of picroside II on bile acid homeostasis via nuclear receptors remains unclear. PurposeThis study was designed to investigate the hepatoprotective effect of picroside II against alpha-naphthylisothiocyanate (ANIT)-induced cholestatic liver injury and elucidate the mechanisms in vivo and in vitro. MethodsThe ANIT-induced cholestatic mouse model was used with or without picroside II treatment. Serum and bile biochemical indicators, as well as liver histopathological changes were examined. siRNA, Dual-luciferase reporter, quantitative real-time PCR and Western blot assay were used to demonstrate the farnesoid X receptor (FXR) pathway in the anti-cholestasis effects of picroside II in vivo and in vitro. ResultsPicroside II exerted hepatoprotective effect against ANIT-induced cholestasis by impaired hepatic function and tissue damage. Picroside II increased bile acid efflux transporter bile salt export pump (Bsep), uptake transporter sodium taurocholate cotransporting polypeptide (Ntcp), and bile acid metabolizing enzymes sulfate transferase 2a1 (Sult2a1) and UDP-glucuronosyltransferase 1a1 (Ugt1a1), whereas decreased the bile acid synthesis enzymes cholesterol 7α-hydroxylase (Cyp7a1) and oxysterol 12α-hydroxylase (Cyp8b1). In addition, expression of FXR and the target gene Bsep was increased, whereas aryl hydrocarbon receptor (AhR), pregnane X receptor (PXR), peroxisome proliferator-activated receptor alpha (PPARα) and their corresponding target genes were not significantly influenced by picroside II under cholestatic conditions. Furthermore, regulation of transporters and enzymes involved in bile acid homeostasis by picroside II were abrogated by FXR silencing in mouse primary cultured hepatocytes. Dual-luciferase reporter assay performed in HepG2 cells demonstrated FXR activation by picroside II. ConclusionOur findings demonstrate that picroside II exerts protective effect on ANIT-induced cholestasis possibly through FXR activation that regulates the transporters and enzymes involved in bile acid homeostasis. Picroside II might be an effective approach for the prevention and treatment of cholestatic liver diseases.

MRX-800: A Long-Term Safety Study of Maralixibat in the Treatment of Cholestatic Liver Disease in Subjects Who Previously Participated in a Maralixibat Study

MRX-800: A Long-Term Safety Study of Maralixibat in the Treatment of Cholestatic Liver Disease in Subjects Who Previously Participated in a Maralixibat Study

Analysis of Flavonoids Bioactivity for Cholestatic Liver Disease: Systematic Literature Search and Experimental Approaches.

Flavonoids are naturally occurring compounds that show health benefits on the liver. However, there is little investigation about identification and evaluation of new flavonoid-containing drugs for cholestatic liver disease, one of the most common liver illnesses. We aimed to a systematic search regarding efficacy of flavonoids for treatment of cholestatic liver disease, and then evaluate naringenin (NG) as representative flavonoid in an obstructive cholestasis model. We searched for information of experimental and clinical studies in four major databases without time and language limits. Intervention was defined as any flavonoid derivate compared with other flavonoid, placebo, or without comparator. In addition, we evaluated NG on a bile duct-ligated model in order to contribute evidence of its actions. Eleven experimental reports that support the efficacy of flavonoids in cholestatic liver disease were identified. However, there was no homogeneity in efficacy endpoints evaluated and methodology. On the other hand, NG showed beneficial effects by improving specific metabolic (cholesterol and lipoproteins) and liver damage (bilirubin and alkaline phosphatase) biomarkers. The review lacks homogeneous evidence about efficacy of flavonoids in experimental settings, and is susceptible to risk for bias. NG only showed improvements in specific disease biomarkers. More investigation is still needed to determine its potential for drug development.

Knockout of secretin receptor reduces biliary damage and liver fibrosis in Mdr2−/− mice by diminishing senescence of cholangiocytes

Secretin receptor (SR), only expressed by cholangiocytes, plays a key role in the regulation of biliary damage and liver fibrosis. The aim of this study was to determine the effects of genetic depletion of SR in Mdr2−/− mice on intrahepatic biliary mass, liver fibrosis, senescence, and angiogenesis. 12 wk SR−/−, Mdr2−/−, and SR−/−/Mdr2−/− mice with corresponding wild-type mice were used for the in vivo studies. Immunohistochemistry or immunofluorescence was performed in liver sections for (i) biliary expression of SR; (ii) hematoxylin and eosin; (iii) intrahepatic biliary mass by CK-19; (iv) fibrosis by Col1a1 and α-SMA; (v) senescence by SA-β-gal and p16; and (vi) angiogenesis by VEGF-A and CD31. Secretin (Sct) and TGF-β1 levels were measured in serum and cholangiocyte supernatant by ELISA. In total liver, isolated cholangiocytes or HSCs, we evaluated the expression of fibrosis markers (FN-1 and Col1a1); senescence markers (p16 and CCL2); microRNA 125b and angiogenesis markers (VEGF-A, VEGFR-2, CD31, and vWF) by immunoblots and/or qPCR. In vitro, we measured the paracrine effect of cholangiocyte supernatant on the expression of senescent and fibrosis markers in human hepatic stellate cells (HHSteCs). The increased level of ductular reaction, fibrosis, and angiogenesis in Mdr2−/− mice was reduced in SR−/−/Mdr2−/− mice. Enhanced senescence levels in cholangiocytes from Mdr2−/− mice were reversed to normal in SR−/−/Mdr2−/− mice. However, senescence was decreased in HSCs from Mdr2−/− mice but returned to normal values in SR−/−/Mdr2−/− mice. In vitro treatment of HHSteCs with supernatant from cholangiocyte lacking SR (containing lower biliary levels of Sct-dependent TGF-β1) have decreased fibrotic reaction and increased cellular senescence. Sct-induced TGF-β1 secretion was mediated by microRNA 125b. Our data suggest that differential modulation of angiogenesis-dependent senescence of cholangiocytes and HSCs may be important for the treatment of liver fibrosis in cholangiopathies.In this study the authors demonstrate that the secretin/secretin receptor axis plays a regulatory role in biliary proliferation and liver fibrosis through differential changes in the senescence of cholangiocytes and hepatic stellate cells in a mouse model of primary sclerosing cholangitis. Targeting senescent cholangiocytes by modulation of the secretin/secretin receptor axis may provide a key therapeutic approach in the treatment of cholestatic liver diseases.

Adherence to ursodeoxycholic acid therapy in patients with cholestatic and autoimmune liver disease

Ursodeoxycholic acid (UDCA) is used for treatment of cholestatic liver diseases and may improve long-term outcome. Although treatment with this hydrophilic bile acid is virtually without side effects, medication adherence might be suboptimal due to patient misconceptions, compromising clinical outcome. Our aim was to evaluate adherence to UDCA in relation to patient beliefs about medicine and to identify potential predictors of poor adherence. Prospective open-label study recruiting patients in treatment with UDCA from April 2016 to March 2017. Adherence was assessed both by the Sensemedic dispenser and by patient-reported adherence, during 12 weeks. Good adherence was defined as ≥ 80% intake. Quality of life (by SF-36) and beliefs about medicine (by BMQ) were also assessed. A total of 75 patients were enrolled (32% primary biliary cholangitis, 31% autoimmune hepatitis, 29% primary sclerosing cholangitis and 8% other conditions). Average adherence according to the medication dispenser was 92 ± 16% (range: 17-100). Eighty-nine percent of the patients exhibited good adherence and 11% poor adherence. According to the BMQ, 42% of all patients were accepting, 50% ambivalent, 8% indifferent and 0% skeptical to UDCA treatment. Poor adherence was associated with young age (P = 0.029) and male gender (P = 0.021). Despite the excellent safety profile of UDCA, still a significant number of patients are poorly adherent. Young age and male sex are associated with poor adherence. Efforts should be made to identify patients with poor adherence and to improve their compliance to therapy.

Review article: therapeutic bile acids and the risks for hepatotoxicity.

Bile acids play important roles in cholesterol metabolism and signal through farnesoid X receptor and G protein-coupled receptors. Given their importance in liver biology, bile acid therapy enables therapeutic applications beyond the treatment of cholestatic liver disease. However, predicting hepatotoxicity of bile acids in humans is obscured due to inconsistent extrapolations of animal data to humans. To review the evidence that could explain discordant bile acids hepatotoxicity observed in humans and animals. Literature search was conducted in PubMed using keywords "bile acid," "transporter," "hepatotoxicity," "clinical study," "animal study," "species difference," "mechanism," "genetic disorder." Relevant articles were selected for review. Clinically significant hepatotoxicity was reported in response to certain bile acids, namely chenodeoxycholic acid, which was given a boxed warning for potential hepatotoxicity. The chemical structure, specifically the number and orientation of hydroxyl groups, significantly affects their hydrophobicity, an important factor in bile acid toxicity. Experimental studies show that hydrophobic bile acids can lead to liver injury through various mechanisms, such as death receptor signalling, mitochondrial dysfunction and inflammation. Although animal studies play a central role in investigating bile acid safety, there are considerable differences in bile acid composition, metabolism and hepatobiliary disposition across species. This does not allow appropriate safety inference, especially for predicting hepatotoxicity in humans. Exploring evidences stemming from inborn errors, genetic models of disease and toxicology studies further improves an understanding of bile acid hepatotoxicity. Species differences should be considered in the development of bile acid related therapeutics. Although the mechanism of bile acid hepatotoxicity is still not fully understood, continued mechanistic studies will deepen our understanding.

Structure-activity relationship study of a series of caspase inhibitors containing γ-amino acid moiety for treatment of cholestatic liver disease

A series of caspase inhibitors containing γ-amino acid moiety have been synthesized. A systemic study on their structure-activity relationship of anti-apoptotic cellular activity is presented. These efforts led to the discovery of compound 20o as a potent caspase inhibitor, which demonstrated preclinical ameliorating total bilirubin efficacy with a significantly improved pharmacokinetic profile.

Discovery of Tropifexor (LJN452), a Highly Potent Non-bile Acid FXR Agonist for the Treatment of Cholestatic Liver Diseases and Nonalcoholic Steatohepatitis (NASH).

The farnesoid X receptor (FXR) is a nuclear receptor that acts as a master regulator of bile acid metabolism and signaling. Activation of FXR inhibits bile acid synthesis and increases bile acid conjugation, transport, and excretion, thereby protecting the liver from the harmful effects of bile accumulation, leading to considerable interest in FXR as a therapeutic target for the treatment of cholestasis and nonalcoholic steatohepatitis. We identified a novel series of highly potent non-bile acid FXR agonists that introduce a bicyclic nortropine-substituted benzothiazole carboxylic acid moiety onto a trisubstituted isoxazole scaffold. Herein, we report the discovery of 1 (tropifexor, LJN452), a novel and highly potent agonist of FXR. Potent in vivo activity was demonstrated in rodent PD models by measuring the induction of FXR target genes in various tissues. Tropifexor has advanced into phase 2 human clinical trials in patients with NASH and PBC.

Schisandrol B protects against cholestatic liver injury through pregnane X receptors.

Currently, ursodeoxycholic acid and obeticholic acid are the only two FDA-approved drugs for cholestatic liver diseases. Thus, new therapeutic approaches need to be developed. Here we have evaluated the anti-cholestasis effects of Schisandrol B (SolB), a bioactive compound isolated from Schisandra sphenanthera. Hepatoprotective effect of SolB against intrahepatic cholestasis, induced by lithocholic acid (LCA), was evaluated in mice. Metabolomic analysis and gene analysis were used to assess involvement of pregnane X receptor (PXR). Molecular docking, cell-based reporter gene analysis and knockout mice were used to demonstrate the critical role of the PXR pathway in the anti-cholestasis effects of SolB. SolB protected against LCA-induced intrahepatic cholestasis. Furthermore, therapeutic treatment with SolB decreased mortality in cholestatic mice. Metabolomics and gene analysis showed that SolB accelerated metabolism of bile acids, promoted bile acid efflux into the intestine, and induced hepatic expression of the PXR-target genes Cyp3a11, Ugt1a1, and Oatp2, which are involved in bile acid homeostasis. Mechanistic studies showed that SolB activated human PXR and up-regulated PXR target genes in human cell lines. Additionally, SolB did not protect Pxr-null mice from liver injury induced by intrahepatic cholestasis, thus providing genetic evidence that the effect of SolB was PXR-dependent. These findings provide direct evidence for the hepatoprotective effects of SolB against cholestasis by activating PXR. Therefore, SolB may provide a new and effective approach to the prevention and treatment of cholestatic liver diseases.

Recent advances in understanding and managing cholestasis.

Cholestatic liver diseases are hereditary or acquired disorders with impaired hepatic excretion and enterohepatic circulation of bile acids and other cholephiles. The distinct pathological mechanisms, particularly for the acquired forms of cholestasis, are not fully revealed, but advances in the understanding of the molecular mechanisms and identification of key regulatory mechanisms of the enterohepatic circulation of bile acids have unraveled common and central mechanisms, which can be pharmacologically targeted. This overview focuses on the central roles of farnesoid X receptor, fibroblast growth factor 19, and apical sodium-dependent bile acid transporter for the enterohepatic circulation of bile acids and their potential as new drug targets for the treatment of cholestatic liver disease.

Regulation of Plasma Membrane Localization of the Na+-taurocholate cotransporting polypeptide (Ntcp) by Hyperosmolarity and Tauroursodeoxycholate

In perfused rat liver, hepatocyte shrinkage induces a Fyn-dependent retrieval of the bile salt export pump (Bsep) and multidrug resistance-associated protein 2 (Mrp2) from the canalicular membrane (Cantore, M., Reinehr, R., Sommerfeld, A., Becker, M., and Haussinger, D. (2011) J. Biol. Chem. 286, 45014-45029) leading to cholestasis. However little is known about the effects of hyperosmolarity on short term regulation of the Na(+)-taurocholate cotransporting polypeptide (Ntcp), the major bile salt uptake system at the sinusoidal membrane of hepatocytes. The aim of this study was to analyze hyperosmotic Ntcp regulation and the underlying signaling events. Hyperosmolarity induced a significant retrieval of Ntcp from the basolateral membrane, which was accompanied by an activating phosphorylation of the Src kinases Fyn and Yes but not of c-Src. Hyperosmotic internalization of Ntcp was sensitive to SU6656 and PP-2, suggesting that Fyn mediates Ntcp retrieval from the basolateral membrane. Hyperosmotic internalization of Ntcp was also found in livers from wild-type mice but not in p47(phox) knock-out mice. Tauroursodeoxycholate (TUDC) and cAMP reversed hyperosmolarity-induced Fyn activation and triggered re-insertion of the hyperosmotically retrieved Ntcp into the membrane. This was associated with dephosphorylation of the Ntcp on serine residues. Insertion of Ntcp by TUDC was sensitive to the integrin inhibitory hexapeptide GRGDSP and inhibition of protein kinase A. TUDC also reversed the hyperosmolarity-induced retrieval of bile salt export pump from the canalicular membrane. These findings suggest a coordinated and oxidative stress- and Fyn-dependent retrieval of sinusoidal and canalicular bile salt transport systems from the corresponding membranes. Ntcp insertion was also identified as a novel target of β1-integrin-dependent TUDC action, which is frequently used in the treatment of cholestatic liver disease.

Therapeutic and Chemopreventive Effects of Ursodeoxycholic Acid (UDCA): Potential Role in Patients with Barrett’s Esophagus

Ursodeoxycholic Acid (UDCA) is widely used for the treatment of cholestatic liver diseases. Major mechanisms of this action are protection of cholangiocytes against cytotoxicity of hydrophobic bile acids, stimulation of hepatobiliary secretion, and protection of hepatocytes against bile acid induced apoptosis. UDCA has also been shown to modulate mitochondrial transmembrane potential and prevent increases in mitochondrial Reactive Oxygen Species (ROS) production. Moreover, UDCA has been shown to have a chemopreventive role in mouse models of colon cancer and in patients with primary sclerosing cholangitis and concomitant In- flammatory Bowel Disease (IBD), low dose UDCA lowers the risk of IBD-associated colorec - tal neoplasia. Our studies suggest that oral UDCA may protect against DNA damage induced by hydrophobic bile acids such as Deoxycholic acid (DCA) in the metaplastic mucosa of patients with Barrett's esophagus. We have found that DCA induces carcinogenic DNA damage in Bar- rett's metaplasia. UDCA which counters the DNA damaging effects of DCA therefore might have a role as a chemopreventive agent in Barrett's metaplasia. Future clinical studies on the use of UDCA for chemoprevention in patients with Barrett's esophagus should be considered.

Regulation of Plasma Membrane Localization of the Na+-Taurocholate Cotransporting Polypeptide (Ntcp) by Hyperosmolarity and Tauroursodeoxycholate

In perfused rat liver, hepatocyte shrinkage induces a Fyn-dependent retrieval of the bile salt export pump (Bsep) and multidrug resistance-associated protein 2 (Mrp2) from the canalicular membrane (Cantore, M., Reinehr, R., Sommerfeld, A., Becker, M., and Häussinger, D. (2011) J. Biol. Chem. 286, 45014-45029) leading to cholestasis. However little is known about the effects of hyperosmolarity on short term regulation of the Na(+)-taurocholate cotransporting polypeptide (Ntcp), the major bile salt uptake system at the sinusoidal membrane of hepatocytes. The aim of this study was to analyze hyperosmotic Ntcp regulation and the underlying signaling events. Hyperosmolarity induced a significant retrieval of Ntcp from the basolateral membrane, which was accompanied by an activating phosphorylation of the Src kinases Fyn and Yes but not of c-Src. Hyperosmotic internalization of Ntcp was sensitive to SU6656 and PP-2, suggesting that Fyn mediates Ntcp retrieval from the basolateral membrane. Hyperosmotic internalization of Ntcp was also found in livers from wild-type mice but not in p47(phox) knock-out mice. Tauroursodeoxycholate (TUDC) and cAMP reversed hyperosmolarity-induced Fyn activation and triggered re-insertion of the hyperosmotically retrieved Ntcp into the membrane. This was associated with dephosphorylation of the Ntcp on serine residues. Insertion of Ntcp by TUDC was sensitive to the integrin inhibitory hexapeptide GRGDSP and inhibition of protein kinase A. TUDC also reversed the hyperosmolarity-induced retrieval of bile salt export pump from the canalicular membrane. These findings suggest a coordinated and oxidative stress- and Fyn-dependent retrieval of sinusoidal and canalicular bile salt transport systems from the corresponding membranes. Ntcp insertion was also identified as a novel target of β1-integrin-dependent TUDC action, which is frequently used in the treatment of cholestatic liver disease.

Expert consensus on the diagnosis and treatment of cholestatic liver disease: an update in 2015

Expert consensus on the diagnosis and treatment of cholestatic liver disease: an update in 2015

Diagnosis and treatment of cholestatic liver disease

Diagnosis and treatment of cholestatic liver disease

Protective effect of bicyclol against bile duct ligation-induced hepatic fibrosis in rats.

To evaluate the protective effect of bicyclol against bile duct ligation (BDL)-induced hepatic fibrosis in rats. Sprague-Dawley male rats underwent BDL and sham-operated animals were used as healthy controls. The BDL rats were divided into two groups which received sterilized PBS or bicyclol (100 mg/kg per day) orally for two consecutive weeks. Serum, urine and bile were collected for biochemical determinations. Liver tissues were collected for histological analysis and a whole genome oligonucleotide microarray assay. Reverse transcription-polymerase chain reaction and Western blotting were used to verify the expression of liver fibrosis-related genes. Treatment with bicyclol significantly reduced liver fibrosis and bile duct proliferation after BDL. The levels of alanine aminotransferase (127.7 ± 72.3 vs 230.4 ± 69.6, P < 0.05) and aspartate aminotransferase (696.8 ± 232.6 vs 1032.6 ± 165.8, P < 0.05) were also decreased by treatment with bicyclol in comparison to PBS. The expression changes of 45 fibrogenic genes and several fibrogenesis-related pathways were reversed by bicyclol in the microarray assay. Bicyclol significantly reduced liver mRNA and/or protein expression levels of collagen 1a1, matrix metalloproteinase 2, tumor necrosis factor, tissue inhibitors of metalloproteinases 2, transforming growth factor-β1 and α-smooth muscle actin. Bicyclol significantly attenuates BDL-induced liver fibrosis by reversing fibrogenic gene expression. These findings suggest that bicyclol might be an effective anti-fibrotic drug for the treatment of cholestatic liver disease.