A Two-Year Clinical Description of a Patient with a Rare Type of Low-GGT Cholestasis Caused by a Novel Variant of USP53.

Here, we report a novel truncating mutation in the ubiquitin-specific peptidase gene (USP53) causing low-γ-GT (GGT) cholestasis. Genetic testing was carried out, including clinical exome sequencing for the proband and Sanger sequencing for the proband and his parents. The proband harbored a novel c.1017_1057del (p.(Cys339TrpfsTer7)) mutation in the ubiquitin carboxyl-terminal hydrolase (UCH) domain of USP53; we describe the clinical and laboratory features of the patient with a rare type of low-GGT cholestasis caused by this variant. The clinical presentation was found to be similar to that of phenotypes described in previous studies. However, there was an unusual presence of liver hemangiomas observed in our patient. Thus, our report reinforces the link between USP53 mutations and cholestasis. With this report, we confirm USP53 as the gene for low-GGT cholestasis and describe liver hemangiomas as a possible additional symptom of the phenotype spectrum. The inclusion of USP53 in the OMIM database and liver gene panels can further increase the effectiveness of molecular genetic studies.

Histone deacetylase 8 inhibition alleviates cholestatic liver injury and fibrosis.

Cholestasis is a pathological condition involving blockage of bile flow that results in hepatotoxicity, inflammation, and fibrosis. Although recent studies have shown that histone deacetylases (HDACs) are involved in the progression of fibrosis in various organs, the role of HDAC8 on liver fibrosis has until now remained unexplored. This study presents a newly-synthesized, selective HDAC8 inhibitor SPA3014 composed of a vinyl disulfide-sulfoxide core, and evaluates its therapeutic efficacy against cholestatic liver injury and fibrosis in bile duct-ligated (BDL) mice. We first observed the increase in HDAC8 protein levels in mice with BDL and patients with cholestatic liver disease. Mice with BDL that were pretreated with SPA3014 had lower liver damage and fibrosis, based on gross examination, histopathologic findings, and biochemical analyses, than did vehicle-treated mice. Studies with LX-2 human hepatic stellate cells showed that SPA3014 exerted protective effects by inhibiting TGF-ß-mediated activation of MAPK-Smad2/3 and JAK2-STAT3 pathways and by upregulating PPARγ expression. Overall, these results strongly suggest that HDAC8 inhibition constitutes a new therapeutic strategy for treatment of cholestatic liver injury.

Quantification of Serum Matrix Metallopeptide 7 Levels May Assist in the Diagnosis and Predict the Outcome for Patients with Biliary Atresia.

OBJECTIVE: To assess the diagnostic and prognostic usefulness of the serum matrix metallopeptidase-7 (MMP-7) level for biliary atresia in infants with cholestasis after hepatoportoenterostomy. STUDY DESIGN: We enrolled 100 infants with cholestasis (age, 43.56 ± 1.97 days; 62 males) with a direct bilirubin level of >1 mg/dL, of whom 36 (36%) were diagnosed with biliary atresisa. The MMP-7 levels in serum samples collected during the cholestasis workup and 6 months after hepatoportoenterostomy were assessed by enzyme-linked immunosorbent assay. We quantified liver fibrosis by Picro Sirius red staining of collagen in specimens from the 81 infants with cholestasis. RESULTS: Infants with biliary atresisa had a significantly higher serum MMP-7 level than that of non-biliary atresisa infants with cholestasis of equivalent age (P < .0001). Receiver operating characteristic analysis showed that a serum MMP-7 level of >1.43 ng/mL was predictive of biliary atresisa in infants with cholestasis (diagnostic accuracy, 88%). There was a positive correlation between the serum MMP-7 level and the severity of liver fibrosis (P = .0002). Survival analysis showed that the frequency of liver transplantation was significantly higher in infants with biliary atresisa with a serum MMP-7 level of >10.30 ng/mL compared with a serum MMP-7 level of ≤10.30 ng/mL after hepatoportoenterostomy (hazard ratio, 4.22; P = .02). CONCLUSIONS: The serum MMP-7 level, which reflects the severity of liver fibrosis and can be determined noninvasively, may facilitate the diagnosis of biliary atresisa among infants with cholestasis. Moreover, the serum MMP-7 level after hepatoportoenterostomy is associated with a need for liver transplantation in infants with biliary atresisa.

Heme oxygenase-1 induction by hemin prevents oxidative stress-induced acute cholestasis in the rat.

We previously demonstrated in in vitro and ex vivo models that physiological concentrations of unconjugated bilirubin (BR) prevent oxidative stress (OS)-induced hepatocanalicular dysfunction and cholestasis. Here, we aimed to ascertain, in the whole rat, whether a similar cholestatic OS injury can be counteracted by heme oxygenase-1 (HO-1) induction that consequently elevates endogenous BR levels. This was achieved through the administration of hemin, an inducer of HO-1, the rate-limiting step in BR generation. We found that BR peaked between 6 and 8 h after hemin administration. During this time period, HO-1 induction fully prevented the pro-oxidant tert-butylhydroperoxide (tBuOOH)-induced drop in bile flow, and in the biliary excretion of bile salts and glutathione, the two main driving forces of bile flow; this was associated with preservation of the membrane localization of their respective canalicular transporters, bile salt export pump (Bsep) and multidrug resistance-associated protein 2 (Mrp2), which are otherwise endocytosed by OS. HO-1 induction counteracted the oxidation of intracellular proteins and membrane lipids induced by tBuOOH, and fully prevented the increase in the oxidized-to-total glutathione (GSHt) ratio, a sensitive parameter of hepatocellular OS. Compensatory elevations of the activity of the antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD) were also prevented. We conclude that in vivo HO-1 induction protects the liver from acute oxidative injury, thus preventing consequent cholestasis. This reveals an important role for the induction of HO-1 and the consequently elevated levels of BR in preserving biliary secretory function under OS conditions, thus representing a novel therapeutic tool to limit the cholestatic injury that bears an oxidative background.

Suggestive hypothesis on a case report: Patient presenting with cyclical ovarian cysts coupled to increased cholestatic enzymes.

We describe the case of a childbearing-age woman presenting with spontaneous recurrent functional ovarian cysts and, more interestingly, chronic and asymptomatic elevation of cholestatic parameters. The patient showed no history of chronic viral infections, immunological and metabolic disorders, alcohol abuse and environmental toxins exposition. Hepatic ultrasonography and cholangio-pancreatography-magnetic-resonance excluded any morphological and structural abnormalities, while liver biopsy evidenced only minimal and not specific features of inflammation. Cholestasis indices obtained prompt recovery after each cycle of synthetic hormone therapy, implanted to treat functional ovarian cysts. She has continuously experienced the off-therapy asynchronous recurrence of liver laboratory abnormalities and functional ovarian cysts. The favorable effect of the synthetic hormone therapy to obtaining a stable recovery of this unexplained long-lasting cholestatic syndrome could be likely explained by downregulation of an endogenous ovarian overproduction, although estrogen-regulated local intracellular transduction pathways cannot be excluded.

Hepatoprotective effects of diosmin and/or sildenafil against cholestatic liver cirrhosis: The role of Keap-1/Nrf-2 and P38-MAPK/NF-κB/iNOS signaling pathway.

The present study was designed to investigate the potential protective effects of diosmin (DS) and/or sildenafil against bile duct ligation (BDL). In order to achieve this goal, BDL was performed to induce liver cirrhosis, DS (100 mg/kg/day, p.o.) and sildenafil (10 mg/kg, twice daily, p.o.) were administrated alone or in combination 24 h after the surgical operation and lasted for 4 weeks. Liver function biomarkers, fibrotic markers, oxidative stress markers, mRNA expression of NF-κB-p65, P38-MAPK, Nrf-2, and Keap-1, as well as protein expression of cytoglobin, NF-κB-p65, Nrf-2, iNOS and eNOS were investigated concomitantly with histopathological study. The results revealed that, 4 weeks of BDL induced a significant alteration in liver functions, fibrotic and oxidative stress markers. Furthermore, up-regulation of NF-κB-p65, P38-MAPK, Keap-1 and iNOS concomitantly with down-regulation of Nrf-2, cytoglobin and eNOS expressions were observed after BDL. DS and/or sildenafil treatment significantly alleviated the disturbance induced by BDL. These findings were further supported by the improvement in histopathological features. Additionally, co-administration of DS and sildenafil were found to significantly improved liver defects due to BDL as compared to the individual drugs. It can be concluded that, DS and sildenafil exhibit hepatoprotective effects through modulation of Keap-1/Nrf-2 and P38-MAPK/NF-κB/iNOS pathway.

Pregnane X receptor and constitutive androstane receptor modulate differently CYP3A-mediated metabolism in early- and late-stage cholestasis.

AIM: To ascertain whether cholestasis affects the expression of two CYP3A isoforms (CYP3A1 and CYP3A2) and of pregnane X receptor (PXR) and constitutive androstane receptor (CAR). METHODS: Cholestasis was induced by bile duct ligation in 16 male Wistar rats; whereas 8 sham-operated rats were used as controls. Severity of cholestasis was assessed on histological examination of liver sections, and serum concentrations of albumin, AST, ALT, GGT, ALPK and bilirubin. Gene and protein expressions of PXR, CAR, CYP3A1 and CYP3A2 were assessed by means of qRT-PCR and Western blot, respectively. Alterations in CYP3A activity were measured by calculating the kinetic parameters of 4-OH and 1'-OH-midazolam hydroxylation, marker reactions for CYP3A enzymes. RESULTS: The mRNA and protein expression of CYP3A1 increased significantly in mild cholestasis (P < 0.01). At variance, mRNA and protein expression of CYP3A2 didn't change in mild cholestasis, whereas the expression and activity of both CYP3A1 and CYP3A2 decreased dramatically when cholestasis became severe. Consistently with these observations, the nuclear expression of both PXR and CAR, which was measured because they both translocate into the cell nucleus after their activation, virtually disappeared in the late stage of cholestatic injury, after an initial increase. These results indicate that early- and late-stage cholestasis affects CYP3A-mediated drug metabolism differently, probably as consequence of the different activation of PXR and CAR. CONCLUSION: Early- and late-stage cholestasis affects CYP3A-mediated drug metabolism differently. PXR and CAR might be targeted therapeutically to promote CYP3A-mediated liver detoxification.

Sildenafil protects against bile duct ligation induced hepatic fibrosis in rats: Potential role for silent information regulator 1 (SIRT1).

Hepatic fibrosis is a potential health problem that may end with life-threatening cirrhosis and primary liver cancer. Recent studies point out to the protective effects of silent information regulator1 (SIRT1), against different models of organs fibrosis. This work aimed to investigate the possible protective effect of sildenafil (SIRT1 activator) against hepatic fibrosis induced by bile duct ligation (BDL). Firstly, three different doses of sildenafil (5, 10, 20mg/kg/day) were investigated; to detect the most protective one against BDL induced liver dysfunction and hepatic fibrosis. The most protective dose is then used; to study its effect on BDL induced SIRT1 downregulation, imbalance of oxidant/antioxidant status, increased inflammatory cytokines and fibrosis. Sildenafil (20mg/kg/day) was the most protective one, it caused upregulation of SIRT1, reduction of hepatic malondialdehyde (MDA) content, increase in expression of nuclear factor erythroid 2-related factor 2 (Nrf2), hemeoxygenease (HO)-1, reduced glutathione (GSH) content and superoxide dismutase (SOD) activity. Hepatic content of tumor necrosis factor-α (TNF-α) and nuclear factor κB (NFκB) expression & content displayed significant reductions with sildenafil treatment, Furthermore, sildenafil caused marked reductions of transforming growth factor (TGF)-ß content, expression of plasminogen activator inhibitor-1 (PAI-1), matrix metalloproteinase-9 (MMP-9), tissue inhibitor of metalloproteinase-1 (TIMP-1), α-smooth muscle actin (α-SMA), fibronectin, collagen I (α1) and hydroxyproline content. However, sildenafil protective effects were significantly reduced by co-administration of EX527 (SIRT1 inhibitor). Our work showed, for the first time that, sildenafil has promising protective effects against BDL induced liver dysfunction and hepatic fibrosis. These effects may be, in part, mediated by up regulation of SIRT1.

Increased cholestatic enzymes in two patients with long-term history of ulcerative colitis: consider primary biliary cholangitis not always primary sclerosing cholangitis.

Several hepatobiliary disorders have been reported in ulcerative colitis (UC) patients with primary sclerosing cholangitis (PSC) being the most specific. Primary biliary cholangitis (PBC), previously known as primary biliary cirrhosis, rarely occurs in UC. We present two PBC cases of 67 and 71 years who suffered from long-standing UC. Both patients were asymptomatic but they had increased cholestatic enzymes and high titres of antimitochondrial antibodies (AMA)-the laboratory hallmark of PBC. After careful exclusion of other causes of cholestasis by MRI/magnetic resonance cholangiopancreatography (MRCP), virological and microbiological investigations, a diagnosis of PBC associated with UC was established. The patients started ursodeoxycholic acid (13 mg/kg/day) with complete response. During follow-up, both patients remained asymptomatic with normal blood biochemistry. Although PSC is the most common hepatobiliary manifestation among patients with UC, physicians must keep also PBC in mind in those with unexplained cholestasis and repeatedly normal MRCP. In these cases, a reliable AMA testing can help for an accurate diagnosis.

Bile acid analysis in human disorders of bile acid biosynthesis.

Bile acids facilitate the absorption of lipids in the gut, but are also needed to maintain cholesterol homeostasis, induce bile flow, excrete toxic substances and regulate energy metabolism by acting as signaling molecules. Bile acid biosynthesis is a complex process distributed across many cellular organelles and requires at least 17 enzymes in addition to different metabolite transport proteins to synthesize the two primary bile acids, cholic acid and chenodeoxycholic acid. Disorders of bile acid synthesis can present from the neonatal period to adulthood and have very diverse clinical symptoms ranging from cholestatic liver disease to neuropsychiatric symptoms and spastic paraplegias. This review describes the different bile acid synthesis pathways followed by a summary of the current knowledge on hereditary disorders of human bile acid biosynthesis with a special focus on diagnostic bile acid profiling using mass spectrometry.

Nimesulide and 4'-Hydroxynimesulide as Bile Acid Transporters Inhibitors Are Contributory Factors for Drug-Induced Cholestasis.

Nimesulide (NIM) is a classic nonsteroidal anti-inflammatory drug. However, some patients treated with NIM experienced cholestatic liver injury. For this reason, we investigated the potential mechanism underlying NIM-induced cholestasis by using in vivo and in vitro models. Oral administration of 100 mg/kg/day NIM to Wistar rats for 5 days increased the levels of plasma total bile acids, alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase by 1.49-, 1.31-, 1.60-, and 1.29-fold, respectively. In sandwich-cultured rat hepatocytes, NIM and 4'-hydroxynimesulide (M1) reduced the biliary excretion index of d8-taurocholic acid (d8-TCA) and 5 (and 6)-carboxy-2',7'-dichlorofluorescein in a concentration-dependent manner, indicating the inhibition of the efflux transporters bile salt export pump and multidrug resistance-associated protein 2, respectively. In suspended rat hepatocytes, NIM and M1 inhibited the uptake transporters of d8-TCA for Na+-taurocholate cotransporting polypeptide at IC50 values of 21.3 and 25.0 µM, respectively, and for organic anion-transporting proteins at IC50 values of 45.6 and 39.4 µM, respectively. By contrast, nitro-reduced NIM and the further acetylated metabolite did not inhibit or only marginally inhibited these transporters at the maximum soluble concentrations. Inhibitory effects of NIM and M1 on human bile acid transporters were also confirmed using sandwich-cultured human hepatocytes. These data suggest that the inhibition of bile acid transporters by NIM and M1 is one of the biologic mechanisms of NIM-induced cholestasis.

Quercetin protects liver injury induced by bile duct ligation via attenuation of Rac1 and NADPH oxidase1 expression in rats.

BACKGROUND: Bile duct ligation (BDL) and subsequent cholestasis are correlated with oxidative stress, hepatocellular injury and fibrosis. Quercetin is a flavonoid with antifibrotic, and hepatoprotective properties. However, the molecular mechanism underlying quercetin-mediated hepatoprotection is not fully understood. The current study was to evaluate mechanisms of hepatoprotective effect of quercetin in BDL rat model. METHODS: We divided male Wistar rats into 4 groups (n=8 for each): sham, sham+quercetin (30 mg/kg per day), BDL, and BDL+quercetin (30 mg/kg per day). Four weeks later, the rats were sacrificed, the blood was collected for liver enzyme measurements and liver for the measurement of Rac1, Rac1-GTP and NOX1 mRNA and protein levels by quantitative PCR and Western blotting, respectively. RESULTS: Quercetin significantly alleviated liver injury in BDL rats as evidenced by histology and reduced liver enzymes. Furthermore, the mRNA and protein expression of Rac1, Rac1-GTP and NOX1 were significantly increased in BDL rats compared with those in the sham group (P<0.05); quercetin treatment reversed these variables back toward normal (P<0.05). Another interesting finding was that the antioxidant markers e.g. superoxide dismutase and catalase were elevated in quercetin-treated BDL rats compared to BDL rats (P<0.05). CONCLUSION: Quercetin demonstrated hepatoprotective activity against BDL-induced liver injury through increasing antioxidant capacity of the liver tissue, while preventing the production of Rac1, Rac1-GTP and NOX1 proteins.

Genetic profiling of children with advanced cholestatic liver disease.

Advanced cholestatic liver disease is a leading referral to pediatric liver transplant centers. Recent advances in the genetic classification of this group of disorders promise a highly personalized management although the genetic heterogeneity also poses a diagnostic challenge. Using a next-generation sequencing-based multi-gene panel, we performed retrospective analysis of 98 pediatric patients who presented with advanced cholestatic liver disease. A likely causal mutation was identified in the majority (61%), spanning many genes including ones that have only rarely been reported to cause cholestatic liver disease, e.g. TJP2 and VIPAS39. We find no evidence to support mono-allelic phenotypic expression in the carrier parents despite the severe nature of the respective mutations, and no evidence of oligogenicity. The high-carrier frequency of the founder mutations identified in our cohort (1 in 87) suggests a minimum incidence of 1:7246, an alarmingly high disease burden that calls for the primary prevention through carrier screening.

Role of AMP-activated protein kinase α1 in 17α-ethinylestradiol-induced cholestasis in rats.

Estrogen-induced cholestasis occurs in many women who are susceptible due to pregnancy or hormone replacement therapy for postmenopausal syndrome. 17α-Ethinylestradiol (EE), as a synthetic estrogen, has been widely used to study the underlying mechanisms of estrogen-induced cholestasis. Recent studies have also reported that liver kinase B1 (LKB1)-mediated activation of AMP-activated protein kinase (AMPK) plays a critical role in the regulation of canalicular network formation. However, the role of AMPK in EE-induced cholestasis remains to be determined. In this study, the effects of EE (1-100 µM) on AMPK activation and the expression of farnesoid X receptor (FXR) and hepatic bile acid transporters were examined in in vitro using 3D-cultured rat primary hepatocytes and in in vivo using rat cholestasis models. We also used specific chemical agonist and antagonist of AMPK, AMPK subunit-specific antibodies and lentiviral shRNAs for AMPKα1 and AMPKα2 to delineate the role of AMPK in EE-induced cholestasis and potential cellular mechanisms. We found that EE-induced phosphorylation of AMPKα1 via extracellular signal-regulated kinases-LKB1-mediated signaling pathways and subsequent nuclear translocation accounted for the down-regulation of FXR and bile acid transporters and disruption of bile acid homeostasis. Inhibition of AMPK activation using an AMPK antagonist Compound C (2 µM) or down-regulation of AMPKα1 using gene-specific shRNA attenuated EE-induced cholestasis both in in vitro and in in vivo. In conclusion, these results revealed that activation of cAMP-ERK-LKB1-AMPKα1 signaling pathway plays a critical role in EE-mediated dysregulation of the expression of FXR and bile acid transporters. AMPKα1 may represent an important therapeutic target for estrogen-induced cholestasis.

Critical and diverse in vivo roles of apoptosis signal-regulating kinase 1 in animal models of atherosclerosis and cholestatic liver injury.

Apoptosis plays pivotal in vivo roles in not only vital processes, such as cell turnover and embryonic development, but also various inflammatory disorders. However, the role of apoptosis by vascular and hepatic cells in the respective progression of atherosclerosis and liver injury remains controversial. Apoptosis signal-regulating kinase 1 (ASK1) is a mitogen-activated protein kinase kinase kinase family member that is activated through distinct mechanisms in response to various cytotoxic stressors. ASK1, ubiquitously expressed, is situated in an important upstream position for many signal transduction pathways, which subsequently induce inflammation and/or apoptosis. Our serial in vivo studies have uniquely reported that the expression of phosphorylated ASK1 is variably seen in atherosclerotic lesions or bile-duct-ligation (BDL)-induced injury livers. In mice genetically deficient of ASK1 (ASK1⁻/⁻), activated ASK1 signaling accelerates high-cholesterol-diet-induced necrotic lipid core formation by inducing macrophage apoptosis and enhances ligation injury-induced vascular remodeling via pro-inflammatory reactions and by stimulating apoptosis of smooth muscle cells. In contrast, in models of BDL-induced cholestatic liver injury, the pathogenic roles of ASK1-mediated early necro-inflammation, but not apoptosis, and the proliferation of hepatocytes and cholangiocytes are crucial in subsequent peribiliary fibrosis/fibrogenesis. These animal models of acute to chronic inflammatory diseases show that stimulated ASK1 signaling critically and diversely regulates not only hypercholesterolemia-induced atherosclerosis and injury-induced arteriosclerosis, but also the acute and subacute-to-chronic phase of BDL-induced cholestasis. We herein review the diverse, key in vivo roles of ASK1 signaling in the pathogenesis of inflammatory disorders closely related to metabolic syndrome.

Changes in Liver Ganglioside Metabolism in Obstructive Cholestasis - the Role of Oxidative Stress.

Bile acids have been implicated in cholestatic liver damage, primarily due to their detergent effect on membranes and induction of oxidative stress. Gangliosides can counteract these harmful effects by increasing the rigidity of the cytoplasmic membrane. Induction of haem oxygenase (HMOX) has been shown to protect the liver from increased oxidative stress. The aim of this study was to determine the changes in the synthesis and distribution of liver gangliosides following bile duct ligation (BDL), and to assess the effects of HMOX both on cholestatic liver injury and ganglioside metabolism. Compared to controls, BDL resulted in a significant increase in total as well as complex gangliosides and mRNA expression of corresponding glycosyltransferases ST3GalV, ST8SiaI and B3GalTIV. A marked shift of GM1 ganglioside from the intracellular compartment to the cytoplasmic membrane was observed following BDL. Induction of oxidative stress by HMOX inhibition resulted in a further increase of these changes, while HMOX induction prevented this effect. Compared to BDL alone, HMOX inhibition in combination with BDL significantly increased the amount of bile infarcts, while HMOX activation decreased ductular proliferation. We have demonstrated that cholestasis is accompanied by significant changes in the distribution and synthesis of liver gangliosides. HMOX induction results in attenuation of the cholestatic pattern of liver gangliosides, while HMOX inhibition leads to the opposite effect.

Up-regulation of BSEP and MRP2 by Calculus Bovis administration in 17α-ethynylestradiol-induced cholestasis: Involvement of PI3K/Akt signaling pathway.

ETHNOPHARMACOLOGY RELEVANCE: Calculus Bovis, also known as Niuhuang, is a rare traditional Chinese medicine that has been widely used in China for 2000 years in pharmacology for sedation, anti-spasm, relieving fever, diminishing inflammation and recovering gallbladder functions. AIM OF THE STUDY: This study aimed to investigate the choleretic potential and molecular responses in rats to Calculus Bovis (CB) administration after 17α-ethynylestradiol (EE)-induced cholestasis. MATERIAL AND METHODS: CB (50 and 100mg/kg per day) was intragastrically (i. g.) given to experimental rats for five consecutive days in coadministration with EE (5mg/kg daily for five days, s.c.). The levels of serum biomarkers were determined biochemically. The histopathology of the liver tissue was evaluated. Expression of bile salt export pump (BSEP) and multidrug resistance-associated protein 2 (MRP2) were studied by western blot and immunohistochemical assay. The expression of Akt and phospho-Akt (pAkt) were also measured by western blot. RESULTS: In response to EE, CB treatment significantly prevented an increase in serum levels of alanine aminotransferase (ALT), alkaline phosphatase (ALP), gamma glutamyltransferase (GGT) and total bilirubin (TBIL). CB treatment also repaired tissue lesions caused by EE. Western blots showed that EE significantly decreased the protein expression of BSEP and MRP2. EE also dramatically increased levels of pAkt and decreased levels of Akt. Compared to the EE group, CB treatment increased levels of hepatic BSEP and MRP2 while pAkt levels decreased and Akt levels increased. Immunohistochemistry also indicated that EE decreased the expression of BSEP and MRP2. LY294002 is a selective PI3K inhibitor and showed similar beneficial effects as CB. Decreased expression of BSEP and MRP2 caused by EE were also prevented by LY294002 treatment. CONCLUSION: Calculus Bovis administration can alleviate liver injury and up-regulate the expression of BSEP and MRP2 in 17α-ethynylestradiol-induced cholestasis by a mechanism that may involve inhibiting the activated PI3K/Akt signaling pathway.

Determination of 7α-OH cholesterol by LC-MS/MS: Application in assessing the activity of CYP7A1 in cholestatic minipigs.

An LC-MS/MS method was developed and validated to determine 7α-OH cholesterol in liver microsome. This method was convenient and fast with high specificity and sensitivity. Briefly, a gradient elution was performed on a Synergi polar-C18 column (50×4.6mm i.d., 3µm). The mobile phase (consisting of 0.1% HCOOH solution and acetonitrile) eluted in gradient at a flow rate of 1ml/min. MS detection was operated on APCI (+) mode; the MRM transitions for 7α-OH cholesterol and D7-cholesterol (I.S.) were 385.1≥159.1 and 376.4≥266.3, respectively. The linear response range of 7α-OH cholesterol was covered from 1.563 to 100.0ng/ml. All of the validation items meet the requirement of FDA guidance for bioanalytical method validation. This method was applied to enzymatic studies for determination of cholesterol 7alpha-hydroxylation activity catalyzed by CYP7A1 in the cholestatic minipigs liver microsomes.