Serum bile acids and cholestasis in alcoholic hepatitis. Relationship with usual liver tests and histological features

Inflammatory liver diseases and susceptibility to sepsis

Patients with inflammatory liver diseases, particularly alcohol-associated liver disease and metabolic dysfunction-associated fatty liver disease (MAFLD), have higher incidence of infections and mortality rate due to sepsis. The current focus in the development of drugs for MAFLD is the resolution of non-alcoholic steatohepatitis and prevention of progression to cirrhosis. In patients with cirrhosis or alcoholic hepatitis, sepsis is a major cause of death. As the metabolic center and a key immune tissue, liver is the guardian, modifier, and target of sepsis. Septic patients with liver dysfunction have the highest mortality rate compared with other organ dysfunctions. In addition to maintaining metabolic homeostasis, the liver produces and secretes hepatokines and acute phase proteins (APPs) essential in tissue protection, immunomodulation, and coagulation. Inflammatory liver diseases cause profound metabolic disorder and impairment of energy metabolism, liver regeneration, and production/secretion of APPs and hepatokines. Herein, the author reviews the roles of (1) disorders in the metabolism of glucose, fatty acids, ketone bodies, and amino acids as well as the clearance of ammonia and lactate in the pathogenesis of inflammatory liver diseases and sepsis; (2) cytokines/chemokines in inflammatory liver diseases and sepsis; (3) APPs and hepatokines in the protection against tissue injury and infections; and (4) major nuclear receptors/signaling pathways underlying the metabolic disorders and tissue injuries as well as the major drug targets for inflammatory liver diseases and sepsis. Approaches that focus on the liver dysfunction and regeneration will not only treat inflammatory liver diseases but also prevent the development of severe infections and sepsis.

Serum bile acids associate with liver volume in polycystic liver disease and decrease upon treatment with lanreotide

BACKGROUND

Polycystic liver disease (PLD) is a common extrarenal manifestation of autosomal dominant polycystic kidney disease (ADPKD). Bile acids may play a role in PLD pathogenesis. We performed a post-hoc exploratory analysis of bile acids in ADPKD patients, who had participated in a trial on the effect of a somatostatin analogue. Our hypothesis was that serum bile acid levels increase in PLD, and that lanreotide, which reduces liver growth, may also reduce bile acid levels. Furthermore, in PLD, urinary excretion of bile acids might contribute to renal disease.

METHODS

With liquid chromatography-mass spectrometry, 11 bile acids in serum and 6 in urine were quantified in 105 PLD ADPKD patients and 52 age-, sex-, mutation- and eGFR-matched non-PLD ADPKD patients. Sampling was done at baseline and after 120 weeks of either lanreotide or standard care.

RESULTS

Baseline serum levels of taurine- and glycine-conjugated bile acids were higher in patients with larger livers. In PLD patients, multiple bile acids decreased upon treatment with lanreotide but remained stable in untreated subjects. Changes over time did not correlate with changes in liver volume. Urine bile acid levels did not change and did not correlate with renal disease progression.

CONCLUSION

In ADPKD patients with PLD, baseline serum bile acids were associated with liver volume. Lanreotide reduced bile acid levels and has previously been shown to reduce liver volume. However, in this study, the decrease in bile acids was not associated with the change in liver volume.

Development of novel liver-targeting glucocorticoid prodrugs

Background

Glucocorticoids (GCs) are widely used in the treatment of inflammatory liver diseases and sepsis, but GC's various side effects on extrahepatic tissues limit their clinical benefits. Liver-targeting GC therapy may have multiple advantages over systemic GC therapy. The purpose of this study was to develop novel liver-targeting GC prodrugs as improved treatment for inflammatory liver diseases and sepsis.

Methods

A hydrophilic linker or an ultra-hydrophilic zwitterionic linker carboxylic betaine (CB) was used to bridge cholic acid (CA) and dexamethasone (DEX) to generate transporter-dependent liver-targeting GC prodrugs CA-DEX and the highly hydrophilic CA-CB-DEX. The efficacy of liver-targeting DEX prodrugs and DEX were determined in primary human hepatocytes (PHH), macrophages, human whole blood, and/or mice with sepsis induced by cecal ligation and puncture.

Results

CA-DEX was moderately water soluble, whereas CA-CB-DEX was highly water soluble. CA-CB-DEX and CA-DEX displayed highly transporter-dependent activities in reporter assays. Data mining found marked dysregulation of many GR-target genes important for lipid catabolism, cytoprotection, and inflammation in patients with severe alcoholic hepatitis. These key GR-target genes were similarly and rapidly (within 6 h) induced or down-regulated by CA-CB-DEX and DEX in PHH. CA-CB-DEX had much weaker inhibitory effects than DEX on endotoxin-induced cytokines in mouse macrophages and human whole blood. In contrast, CA-CB-DEX exerted more potent anti-inflammatory effects than DEX in livers of septic mice.

Conclusions

CA-CB-DEX demonstrated good hepatocyte-selectivity in vitro and better anti-inflammatory effects in vivo. Further test of CA-CB-DEX as a novel liver-targeting GC prodrug for inflammatory liver diseases and sepsis is warranted.

Alcohol use associated alterations in the circulating metabolite profile in the general population and in individuals with major depressive disorder

Our aim was to evaluate whether alcohol use is associated with changes in the circulating metabolite profile similar to those present in persons with depression. If so, these findings could partially explain the link between alcohol use and depression. We applied a targeted liquid chromatography mass spectrometry method to evaluate correlates between concentrations of 86 circulating metabolites and self-reported alcohol use in a cohort of the non-depressed general population (GP) (n = 247) and a cohort of individuals with major depressive disorder (MDD) (n = 99). Alcohol use was associated with alterations in circulating concentrations of metabolites in both cohorts. Our main finding was that self-reported alcohol use was negatively correlated with serum concentrations of hippuric acid in the GP cohort. In the GP cohort, consumption of six or more doses per week was associated with low hippuric acid concentrations, similar to those observed in the MDD cohort, but in these individuals it was regardless of their level of alcohol use. Reduced serum concentrations of hippuric acid suggest that already moderate alcohol use is associated with depression-like changes in the serum levels of metabolites associated with gut microbiota and liver function; this may be one possible molecular level link between alcohol use and depression.

Apical bulkheads accumulate as adaptive response to impaired bile flow in liver disease

Hepatocytes form bile canaliculi that dynamically respond to the signalling activity of bile acids and bile flow. Little is known about their responses to intraluminal pressure. During embryonic development, hepatocytes assemble apical bulkheads that increase the canalicular resistance to intraluminal pressure. Here, we investigate whether they also protect bile canaliculi against elevated pressure upon impaired bile flow in adult liver. Apical bulkheads accumulate upon bile flow obstruction in mouse models and patients with primary sclerosing cholangitis (PSC). Their loss under these conditions leads to abnormally dilated canaliculi, resembling liver cell rosettes described in other hepatic diseases. 3D reconstruction reveals that these structures are sections of cysts and tubes formed by hepatocytes. Mathematical modelling establishes that they positively correlate with canalicular pressure and occur in early PSC stages. Using primary hepatocytes and 3D organoids, we demonstrate that excessive canalicular pressure causes the loss of apical bulkheads and formation of rosettes. Our results suggest that apical bulkheads are a protective mechanism of hepatocytes against impaired bile flow, highlighting the role of canalicular pressure in liver diseases.

Enhanced diagnosis and prognosis of severe alcoholic hepatitis using novel metabolomic biomarkers

AIM

Differentiating alcoholic hepatitis (AH) from acute decompensation of alcoholic cirrhosis (DC) is challenging, as the presentation and biochemistry are similar. We aimed to identify potential metabolomic biomarkers to differentiate between AH and DC, and to predict short-term mortality.

METHODS

We included consecutive biopsy proven AH and DC patients, which were managed according to current guidelines and followed up until the end of the study. Untargeted metabolomics was assessed in all patients at baseline. Specific analyses were successively performed to identify potential biomarkers, which were further semi-quantitatively analysed against relevant clinical endpoints.

RESULTS

Thirty-four patients with AH and 37 with DC were included. UHPLC-MS analysis identified 83 molecules potentially differentiating between AH and DC. C16-Sphinganine-1P (S1P) was the most increased, whereas Prostaglandin E2 (PGE2) was the most decreased. The PGE2/S1P ratio < 1.03 excellently discriminates between AH and DC: AUC 0.965 (p < 0.001), Se 90%, Sp 100%, PPV 0.91, NPV 1, and diagnostic accuracy 95%. This ratio is not influenced by the presence of infection (AUC 0.967 vs. 0.962), correlates with the Lille score at 7 days (r = -0.60; P = 0.022) and tends to be lower in corticosteroid non-responders as compared with patients who responded [0.85(±0.02) vs. 0.89(±0.05), P = 0.069]. Additionally, decreased ursodeoxycholic acid levels are correlated with MELD and Maddrey scores and predict mortality with a 77.27% accuracy (NPV = 100%).

CONCLUSION

This study suggests the PGE2 (decreased)/S1P (increased) ratio as a biomarker to differentiate AH from DC. The study also finds that low levels of ursodeoxycholic acid could predict increased mortality in AH.

Altered ethanol metabolism and increased oxidative stress enhance alcohol-associated liver injury in farnesoid X receptor-deficient mice

BACKGROUND & AIMS

Pharmacological activation of farnesoid X receptor (FXR) ameliorates liver injury, steatosis and inflammation in mouse models of alcoholic liver disease (ALD), but the underlying mechanisms of the protective effect of FXR against ALD remain unclear.

METHODS

To investigate the role of FXR in ALD, we used the NIAAA model of chronic plus binge ethanol feeding in FXR-deficient knockout (FXR KO) mice.

RESULTS

Ethanol-mediated liver injury and steatosis were increased in FXR KO mice, while both WT and FXR KO mice consumed the same amount of alcohol. Ethanol feeding induced liver inflammation and neutrophil infiltration that were further increased in FXR KO mice. In addition, collagen accumulation and expression of profibrotic genes were markedly elevated in the liver of alcohol-fed FXR KO compared to wild-type mice, suggesting that ethanol-induced liver fibrosis is enhanced in the absence of FXR. Surprisingly, FXR KO mice showed reduced blood alcohol levels post-binge, while CYP2E1 and ALDH1A1 were upregulated compared to WT mice, suggesting that alcohol metabolism is altered in FXR KO mice. Notably, exacerbated liver injury in FXR KO mice was associated with increased oxidative stress. ALDH1A1 activity was upregulated in FXR-deficient mouse primary hepatocytes, contributing to reactive oxygen species (ROS) generation, in vitro. Finally, using an ALDH1A1 inhibitor, we showed that ALDH1A1 activity is a key contributor to alcohol-induced ROS generation in FXR-deficient hepatocytes, in vitro.

CONCLUSION

ALD pathogenesis in FXR KO mice correlates with altered ethanol metabolism and increased oxidative stress, providing new insights into the protective function of FXR in ALD.

Narrative Review: Glucocorticoids in Alcoholic Hepatitis—Benefits, Side Effects, and Mechanisms

Alcoholic hepatitis is a major health and economic burden worldwide. Glucocorticoids (GCs) are the only first-line drugs recommended to treat severe alcoholic hepatitis (sAH), with limited short-term efficacy and significant side effects. In this review, I summarize the major benefits and side effects of GC therapy in sAH and the potential underlying mechanisms. The review of the literature and data mining clearly indicate that the hepatic signaling of glucocorticoid receptor (GR) is markedly impaired in sAH patients. The impaired GR signaling causes hepatic down-regulation of genes essential for gluconeogenesis, lipid catabolism, cytoprotection, and anti-inflammation in sAH patients. The efficacy of GCs in sAH may be compromised by GC resistance and/or GC’s extrahepatic side effects, particularly the side effects of intestinal epithelial GR on gut permeability and inflammation in AH. Prednisolone, a major GC used for sAH, activates both the GR and mineralocorticoid receptor (MR). When GC non-responsiveness occurs in sAH patients, the activation of MR by prednisolone might increase the risk of alcohol abuse, liver fibrosis, and acute kidney injury. To improve the GC therapy of sAH, the effort should be focused on developing the biomarker(s) for GC responsiveness, liver-targeting GR agonists, and strategies to overcome GC non-responsiveness and prevent alcohol relapse in sAH patients.

Recent advances on FXR-targeting therapeutics

The bile acid receptor FXR has emerged as a bona fide drug target for chronic cholestatic and metabolic liver diseases, ahead of all non-alcoholic fatty liver disease (NAFLD). FXR is highly expressed in the liver and intestine and activation at both sites differentially contributes to its desired metabolic effects. Unrestricted FXR activation, however, also comes along with undesired effects such as a pro-atherogenic lipid profile, pruritus and hepatocellular toxicity under certain conditions. Several pre-clinical studies have confirmed the potency of FXR activation for cholestatic and metabolic liver diseases, but overall it remains still open whether selective activation of intestinal FXR is advantageous over pan-FXR activation and whether restricted or modulated FXR activation can limit some of the side effects. Even more, FXR antagonist also bear the potential as intestinal-selective drugs in NAFLD models. In this review we will discuss the molecular prerequisites for FXR activation, pan-FXR activation and intestinal FXR in/activation from a therapeutic point of view, different steroidal and non-steroidal FXR agonists, ways to restrict FXR activation and finally what we have learned from pre-clinical models and clinical trials with different FXR therapeutics.

Development of Alcohol-Associated Hepatitis Is Associated With Specific Changes in Gut-Modified Bile Acids

The perturbations in bile acids (BAs) in alcohol-associated hepatitis (AH) and its relationship to disease severity is not well defined. The aims of this study were to define (1) the effects of heavy alcohol consumption on BAs and related microbiome, (2) the additional changes with AH, and (3) the relationship of these changes to disease severity. In this multicenter study, plasma and fecal BAs and related microbiome were interrogated in healthy individuals, heavy drinking controls (HDCs) without overt liver disease, and AH. Compared to healthy controls, HDCs had increased glycine-conjugated 7α and 27α primary BAs and increased secondary BA glycocholenic sulfate (multiple-comparison adjusted P < 0.05 for all). Plasma-conjugated cholic and chenodeoxycholic acid increased in AH along with the secondary BAs ursodeoxycholic and lithocholic acid (P < 0.001 for all), whereas deoxycholic acid decreased; however fecal concentrations of both deoxycholic acid and lithocholic acid were decreased. Glycocholenic acid further increased significantly from HDCs to AH. HDCs and AH had distinct plasma and fecal BA profiles (area under the curve, 0.99 and 0.93, respectively). Plasma taurochenodeoxycholic acid and tauroursodeoxycholic acid were directly related to disease severity, whereas fecal ursodeoxycholic acid was inversely related. The fecal abundance of multiple taxa involved in formation of secondary BAs, especially deoxycholic acid (Clostridium cluster XIVa) was decreased in AH. Multiple genera containing taxa expressing 3α, 3β, 7α, and 7β epimerases were decreased with concordant changes in fecal BAs that required these functions for formation. Conclusion: There are distinct changes in BA-transforming microbiota and corresponding BAs in AH that are related to disease severity.

The Serum Profile of Transferrin Isoforms in Pancreatitis

Total transferrin concentration changes in acute-phase reactions. Additionally, the alteration of transferrin glycosylation in inflammations can occur. The aim of this study is to evaluate the effect of pancreatitis on the serum profile of transferrin isoforms. The tested groups consisted of 84 patients with acute pancreatitis and 42 patients with chronic hepatitis. Transferrin isoforms were analyzed by capillary electrophoresis on a MINICAP electrophoretic system (Sebia, France). There was a significant decrease in the concentration of pentasialotransferrin in both acute and chronic pancreatitis, and a significant increase in tetrasialotransferrin in the acute pancreatitis group when compared to the control group. There were no significant changes in transferrin isoforms between the acute and chronic pancreatitis groups, and between the edematous and necrotizing forms of the disease. Considering the etiology of acute pancreatitis, we noticed higher values of bile acids and γ-glutamyltransferase in acute pancreatitis of alcoholic etiology than that in pancreatitis of other etiologies. In conclusion, the alterations in transferrin isoform profile in acute and chronic pancreatitis are not organ specific. Because similar changes were observed in hepatitis, we can conclude that the serum profile of transferrin isoforms is involved in the pathogenesis of the disease.

Use of bile acids as potential markers of liver dysfunction in humans: A systematic review

OBJECTIVE

This study aimed to determine the effectiveness of using total, individual serum, or urinary bile acids (BA) as potential markers of liver dysfunction.

METHODS

We searched the PubMed and Web of Science databases using the following keywords- "serum bile acids," "liver dysfunction," "liver injury," "liver disease," "traditional liver function tests," "Chronic liver disease," "acute liver injury". The search was complemented by manual screening of the list of references for relevant articles. We selected only English-language manuscripts for adult patients based on predetermined inclusion and exclusion criteria. Animal studies and studies on neonates and children were not included.

OUTCOME MEASURES

Changes in BA concentrations or ratios at or prior to changes in liver function tests.

RESULTS

A total of 547 studies were identified, of which 28 were included after reading the entire manuscript. These studies included 1630 patients and 836 controls published between 1990 and 2017. The methods used in BA assays varied significantly, and the studies did not agree. on specific individual BA or BA ratios as biomarkers of specific liver injury or dysfunction. Except for the prognostic value of BA in intrahepatic cholestasis of pregnancy (ICP), studies have failed to provide evidence for BA as a liver biomarker.

CONCLUSIONS

Despite the research conducted on BA for over 27 years, there are inconsistencies in the reported results and a lack of solid evidence to support the use of individual BA or BA ratios as biomarkers of liver injury. Adequately conducted studies needed to resolve this limitation in the literature.

Fibroblast Growth Factor 21 Response in a Preclinical Alcohol Model of Acute-on-Chronic Liver Injury

BACKGROUND AND AIMS

Fibroblast growth factor (FGF) 21 has recently been shown to play a potential role in bile acid metabolism. We aimed to investigate the FGF21 response in an ethanol-induced acute-on-chronic liver injury (ACLI) model in Abcb4-/- mice with deficiency of the hepatobiliary phospholipid transporter.

METHODS

Total RNA was extracted from wild-type (WT, C57BL/6J) and Abcb4-/- (KO) mice, which were either fed a control diet (WT-Cont and KO-Cont groups; n = 28/group) or ethanol diet, followed by an acute ethanol binge (WT-EtOH and KO-EtOH groups; n = 28/group). A total of 58 human subjects were recruited into the study, including patients with alcohol-associated liver disease (AALD; n = 31) and healthy controls (n = 27). The hepatic and ileal expressions of genes involved in bile acid metabolism, plasma FGF levels, and bile acid and its precursors 7α- and 27-hydroxycholesterol (7α- and 27-OHC) concentrations were determined. Primary mouse hepatocytes were isolated for cell culture experiments.

RESULTS

Alcohol feeding significantly induced plasma FGF21 and decreased hepatic Cyp7a1 levels. Hepatic expression levels of Fibroblast growth factor receptor 1 (Fgfr1), Fgfr4, Farnesoid X-activated receptor (Fxr), and Small heterodimer partner (Shp) and plasma FGF15/FGF19 levels did not differ with alcohol challenge. Exogenous FGF21 treatment suppressed Cyp7a1 in a dose-dependent manner in vitro. AALD patients showed markedly higher FGF21 and lower 7α-OHC plasma levels while FGF19 did not differ.

CONCLUSIONS

The simultaneous upregulation of FGF21 and downregulation of Cyp7a1 expressions upon chronic plus binge alcohol feeding together with the invariant plasma FGF15 and hepatic Shp and Fxr levels suggest the presence of a direct regulatory mechanism of FGF21 on bile acid homeostasis through inhibition of CYP7A1 by an FGF15-independent pathway in this ACLI model. Lay Summary: Alcohol challenge results in the upregulation of FGF21 and repression of Cyp7a1 expressions while circulating FGF15 and hepatic Shp and Fxr levels remain constant both in healthy and pre-injured livers, suggesting the presence of an alternative FGF15-independent regulatory mechanism of FGF21 on bile acid homeostasis through the inhibition of Cyp7a1.

Colesevelam Reduces Ethanol-Induced Liver Steatosis in Humanized Gnotobiotic Mice

Alcohol-related liver disease is associated with intestinal dysbiosis. Functional changes in the microbiota affect bile acid metabolism and result in elevated serum bile acids in patients with alcohol-related liver disease. The aim of this study was to identify the potential role of the bile acid sequestrant colesevelam in a humanized mouse model of ethanol-induced liver disease. We colonized germ-free (GF) C57BL/6 mice with feces from patients with alcoholic hepatitis and subjected humanized mice to the chronic–binge ethanol feeding model. Ethanol-fed gnotobiotic mice treated with colesevelam showed reduced hepatic levels of triglycerides and cholesterol, but liver injury and inflammation were not decreased as compared with non-treated mice. Colesevelam reduced hepatic cytochrome P450, family 7, subfamily a, polypeptide 1 (Cyp7a1) protein expression, although serum bile acids were not lowered. In conclusion, our findings indicate that colesevelam treatment mitigates ethanol-induced liver steatosis in mice.

Metabolic Profiling of Bile Acids in the Urine of Patients with Alcohol-Associated Liver Disease

Bile acids (BAs) play important functions in the development of alcohol-associated liver disease (ALD). In the current study, urine BA concentrations in 38 patients with well-described alcohol-associated hepatitis (AH) as characterized by Model for End-Stage Liver Disease (MELD), 8 patients with alcohol-use disorder (AUD), and 19 healthy controls (HCs) were analyzed using liquid chromatography-mass spectrometry. Forty-three BAs were identified, and 22 BAs had significant changes in their abundance levels in patients with AH. The potential associations of clinical data were compared to candidate BAs in this pilot proof-of-concept study. MELD score showed positive correlations with several conjugated BAs and negative correlations with certain unconjugated BAs; taurine-conjugated chenodeoxycholic acid (CDCA) and MELD score showed the highest association. Cholic acid, CDCA, and apocholic acid had nonsignificant abundance changes in patients with nonsevere ALD compared to HCs but were significantly increased in those with severe AH. Receiver operating characteristic analysis showed that the differences in these three compounds were sufficiently large to distinguish severe AH from nonsevere ALD. Notably, the abundance levels of primary BAs were significantly increased while most of the secondary BAs were markedly decreased in AH compared to AUD. Most importantly, the amount of total BAs and the ratio of primary to secondary BAs increased while the ratio of unconjugated to conjugated BAs decreased as disease severity increased. Conclusion: Abundance changes of specific BAs are closely correlated with the severity of AH in this pilot study. Urine BAs (individually or as a group) could be potential noninvasive laboratory biomarkers for detecting early stage ALD and may have prognostic value in AH morbidity.

Liquid Biopsy for the Diagnosis of Viral Hepatitis, Fatty Liver Steatosis, and Alcoholic Liver Diseases

During the progression from hepatitis to fibrosis, cirrhosis, and liver failure, the accumulation of stressed/damaged hepatocyte elements associated with liver inflammation is critical. The causes of hepatocyte injuries include viral hepatitis infections, alcoholic hepatitis, and non-alcoholic fatty liver disease. Hepatocyte-derived extracellular vesicles (Hep-EVs) released from stressed/damaged hepatocytes are partly responsible for liver disease progression and liver damage because they activate non-parenchymal cells and infiltrate inflammatory cells within the liver, which are in turn are an important source of EVs. This cell-to-cell signaling is prevalent during inflammation in many liver diseases. Accordingly, special emphasis should be placed on liquid biopsy methods for the long-term monitoring of chronic liver diseases. In the present review, we have highlighted various aspects of current liquid biopsy research into chronic liver diseases. We have also reviewed recent progress on liquid biopsies that focus on cell-free DNA (cfDNA), long non-coding RNA (lncRNA), and the proteins in EVs as potential diagnostic tools and novel therapeutic targets in patients with viral hepatitis, fatty liver steatosis, and alcoholic liver diseases.

Bile acid homeostasis and intestinal dysbiosis in alcoholic hepatitis

BACKGROUND

Intestinal microbiota plays an important role in bile acid homeostasis.

AIM

To study the structure of the intestinal microbiota and its function in bile acid homeostasis in alcoholic patients based on the severity of alcoholic liver disease.

METHODS

In this prospective study, we included four groups of active alcoholic patients (N = 108): two noncirrhotic, with (noCir_AH, n = 13) or without alcoholic hepatitis (noCir_noAH, n = 61), and two cirrhotic, with (Cir_sAH, n = 17) or without severe alcoholic hepatitis (Cir_noAH, n = 17). Plasma and faecal bile acid profiles and intestinal microbiota composition were assessed.

RESULTS

Plasma levels of total bile acids (84.6 vs 6.8 μmol/L, P < 0.001) and total ursodeoxycholic acid (1.3 vs 0.3 μmol/L, P = 0.03) were higher in cirrhosis with severe alcoholic hepatitis (Cir_sAH) than Cir_noAH, whereas total faecal (2.4 vs 11.3, P = 0.01) and secondary bile acids (0.7 vs 10.7, P < 0.01) levels were lower. Cir_sAH patients had a different microbiota than Cir_noAH patients: at the phyla level, the abundance of Actinobacteria (9 vs 1%, P = 0.01) was higher and that of Bacteroidetes was lower (25 vs 40%, P = 0.04). Moreover, the microbiota of Cir_sAH patients showed changes in the abundance of genes involved in 15 metabolic pathways, including upregulation of glutathione metabolism, and downregulation of biotin metabolism.

CONCLUSIONS

Patients with Cir_sAH show specific changes of the bile acid pool with a shift towards more hydrophobic and toxic species that may be responsible for the specific microbiota changes. Conversely, the microbiota may also alter the bile acid pool by transforming primary to secondary bile acids, leading to a vicious cycle.

Dysregulation of serum bile acids and FGF19 in alcoholic hepatitis

BACKGROUND & AIMS

The degree of cholestasis is an important disease driver in alcoholic hepatitis, a severe clinical condition that needs new biomarkers and targeted therapies. We aimed to identify the largely unknown mechanisms and biomarkers linked to cholestasis in alcoholic hepatitis.

METHODS

Herein, we analyzed a well characterized cohort of patients with alcoholic hepatitis and correlated clinical and histological parameters and outcomes with serum bile acids and fibroblast growth factor 19 (FGF19), a major regulator of bile acid synthesis.

RESULTS

We found that total and conjugated bile acids were significantly increased in patients with alcoholic hepatitis compared with controls. Serum FGF19 levels were strongly increased and gene expression of FGF19 was induced in biliary epithelial cells and ductular cells of patients with alcoholic hepatitis. De novo bile acid synthesis (CYP7A1 gene expression and C4 serum levels) was significantly decreased in patients with alcoholic hepatitis. Importantly, total and conjugated bile acids correlated positively with FGF19 and with disease severity (model for end-stage liver disease score). FGF19 correlated best with conjugated cholic acid, and model for end-stage liver disease score best with taurine-conjugated chenodeoxycholic acid. Univariate analysis demonstrated significant associations between FGF19 and bilirubin as well as gamma glutamyl transferase, and negative correlations between FGF19 and fibrosis stage as well as polymorphonuclear leukocyte infiltration, in all patients with alcoholic hepatitis.

CONCLUSION

Serum FGF19 and bile acids are significantly increased in patients with alcoholic hepatitis, while de novo bile acid synthesis is suppressed. Modulation of bile acid metabolism or signaling could represent a promising target for treatment of alcoholic hepatitis in humans.

LAY SUMMARY

Understanding the underlying mechanisms that drive alcoholic hepatitis is important for the development of new biomarkers and targeted therapies. Herein, we describe a molecule that is increased in patients with alcoholic hepatitis. Modulating the molecular pathway of this molecule might lead to promising targets for the treatment of alcoholic hepatitis.

Alcoholic Hepatitis: Lost in Translation

Alcoholic hepatitis is the most severe and acute form of alcoholic liver disease. The mortality rate associated with alcoholic hepatitis is high, largely due to the lack of suitable pharmacological interventions. While there has been substantial research in the area, generating pharmacological interventions has been plagued by the lack of a robust mouse model both for testing and for understanding the underlying pathology. A number of major notable advances have been made in this area recently, with the goal of generating a mouse model of alcoholic hepatitis. The purpose of this article is to review recent advances in modeling alcoholic liver disease both in vitro and in vivo in the mouse, and place them in the context of the greater spectrum of alcoholic liver disease, with a focus on how we can translate current advances into a high-fidelity model of alcoholic hepatitis. In addition, we will review the basic mechanisms of alcoholic hepatitis as it is currently understood, focusing on recent advancements in diagnosis, prognosis and current pathophysiology, especially as it relates to the profound immune dysfunction present during alcoholic hepatitis.

Target profiling analyses of bile acids in the evaluation of hepatoprotective effect of gentiopicroside on ANIT-induced cholestatic liver injury in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Gentiopicroside (GPS), one of iridoid glucoside representatives, is the most potential active component in Gentiana rigescens Franch. ex Hemsl and Gentiana macrophylla Pall. These two herbs have been used to treat jaundice and other hepatic and billiary diseases in traditional Chinese medicine for thousands of years.

AIM OF THE STUDY

This study aimed to investigate the protective effects and mechanisms of GPS on α-naphthylisothiocyanate (ANIT) induced cholestatic liver injury in mice.

MATERIALS AND METHODS

Mice were treated with GPS (130mg/kg, ig) for 5 consecutive days. On the third day, mice were given a single dose of Alpha-naphthylisothiocyanate (75mg/kg, ig). Serum biochemical markers and individual bile acids in serum, liver, urine and feces were measured at different time points after ANIT administration. The expression of hepatic bile acid synthesis, uptake and transporter genes as well as ileum bile acid transporter genes were assayed.

RESULTS

In this study, ANIT exposure resulted in serious cholestasis with liver injury, which was demonstrated by dramatically increased serum levels of ALT, ALP, TBA and TBIL along with TCA CA, MCAs and TMCAs accumulation in both liver and serum. Furthermore, ANIT significantly decreased bile acid synthesis related gene expressions, and increased expression of bile acid transporters in liver. Continuous treatment with GPS attenuated ANIT-induced acute cholestasis as well as liver injury and correct the dyshomeostasis of bile acids induced by ANIT. Our data showed that GPS significantly upregulated the hepatic mRNA levels of synthesis enzymes (Cyp8b1 and Cyp27a1) and transporters (Mrp4 Mdr1 and Ost-β) as well as ileal bile acid circulation mediators (Asbt and Fgf15), accompanied by serum and hepatic bile acid levels decrease and further urinary and fecal bile acid levels increase.

CONCLUSION

GPS can change bile acids metabolism which highlights its importance in mitigating cholestasis, resulting in the marked decrease of intracellular bile acid pool back toward basal levels. And the protective mechanism was associated with regulation of bile acids-related transporters, but the potential mechanism warrants further investigation.

Circadian clock control of hepatic lipid metabolism: role of small heterodimer partner (Shp)

Hepatic steatosis, the accumulation of triglyceride droplets in the hepatocytes, is a common hepatic pathology seen in subjects with obesity/metabolic syndrome and those with excessive alcohol use. The pathogenesis underlying hepatic steatosis is complex. Recent studies have shown the specific role played by the molecular clock mechanism in the control of lipid metabolism and that the disruption of these tissue clocks may lead to the disturbances in lipid homeostasis. This review reports a novel role of small heterodimer partner in maintaining triglyceride and lipoprotein homeostasis through neuronal PAS domain protein 2.

A synthetic biology-based device prevents liver injury in mice

BACKGROUND & AIMS

The liver performs a panoply of complex activities coordinating metabolic, immunologic and detoxification processes. Despite the liver's robustness and unique self-regeneration capacity, viral infection, autoimmune disorders, fatty liver disease, alcohol abuse and drug-induced hepatotoxicity contribute to the increasing prevalence of liver failure. Liver injuries impair the clearance of bile acids from the hepatic portal vein which leads to their spill over into the peripheral circulation where they activate the G-protein-coupled bile acid receptor TGR5 to initiate a variety of hepatoprotective processes.

METHODS

By functionally linking activation of ectopically expressed TGR5 to an artificial promoter controlling transcription of the hepatocyte growth factor (HGF), we created a closed-loop synthetic signalling network that coordinated liver injury-associated serum bile acid levels to expression of HGF in a self-sufficient, reversible and dose-dependent manner.

RESULTS

After implantation of genetically engineered human cells inside auto-vascularizing, immunoprotective and clinically validated alginate-poly-(L-lysine)-alginate beads into mice, the liver-protection device detected pathologic serum bile acid levels and produced therapeutic HGF levels that protected the animals from acute drug-induced liver failure.

CONCLUSIONS

Genetically engineered cells containing theranostic gene circuits that dynamically interface with host metabolism may provide novel opportunities for preventive, acute and chronic healthcare.

LAY SUMMARY

Liver diseases leading to organ failure may go unnoticed as they do not trigger any symptoms or significant discomfort. We have designed a synthetic gene circuit that senses excessive bile acid levels associated with liver injuries and automatically produces a therapeutic protein in response. When integrated into mammalian cells and implanted into mice, the circuit detects the onset of liver injuries and coordinates the production of a protein pharmaceutical which prevents liver damage.

Alcoholic vs non-alcoholic fatty liver in rats: distinct differences in endocytosis and vesicle trafficking despite similar pathology

Background

Non-alcoholic and alcoholic fatty liver disease (NAFLD and AFLD, respectively) are major health problems, as patients with either condition can progress to hepatitis, fibrosis, and cirrhosis. Although histologically similar, key differences likely exist in these two models. For example, altered content of several vesicle trafficking proteins have been identified in AFLD, but their content in NAFLD is unknown. In this study, we compared select parameters in NAFLD and AFLD in a rat model.

Methods

We fed either Lieber- DeCarli liquid control or alcohol-containing (35 % as calories) diet (AFLD model) or lean or high-fat (12 or 60 % derived from fat, respectively) pellets (NAFLD model) for 8–10 weeks, n = 8 in each model. Serum, hepatocytes and liver tissue were analyzed. Liver injury markers were measured in serum, triglyceride content and endocytosis (binding and internalization of ¹²⁵I- asialoorosomucoid) was measured in isolated hepatocytes, and content of selected trafficking proteins (Rab3D, Rab7 and Rab18) were determined in whole liver tissue.

Results

Although liver injury markers and triglyceride content were similar in both models, binding and internalization of ¹²⁵I- asialoorosomucoid was significantly impaired in the hepatocytes from AFLD, but not NAFLD, animals. In addition, protein content of the asialoglycoprotein receptor (ASGPR) and three trafficking proteins, Rab3D, Rab7and Rab18, were significantly decreased after alcohol, but not high-fat feeding. Levels of protein carbonylation, amount of glutathione stores, and lipid peroxidation were similar irrespective of the insult to the livers that resulted in fatty liver.

Conclusion

Impairments in protein trafficking in AFLD are likely a direct result of alcohol administration, and not a function of fatty liver.

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.

SIRT1 controls liver regeneration by regulating bile acid metabolism through farnesoid X receptor and mammalian target of rapamycin signaling

Sirtuin1 (SIRT1) regulates central metabolic functions such as lipogenesis, protein synthesis, gluconeogenesis, and bile acid (BA) homeostasis through deacetylation. Here we describe that SIRT1 tightly controls the regenerative response of the liver. We performed partial hepatectomy (PH) to transgenic mice that overexpress SIRT1 (SIRT). SIRT mice showed increased mortality, impaired hepatocyte proliferation, BA accumulation, and profuse liver injury after surgery. The damaging phenotype in SIRT mice correlated with impaired farnesoid X receptor (FXR) activity due to persistent deacetylation and lower protein expression that led to decreased FXR-target gene expression; small heterodimer partner (SHP), bile salt export pump (BSEP), and increased Cyp7A1. Next, we show that 24-norUrsodeoxycholic acid (NorUDCA) attenuates SIRT protein expression, increases the acetylation of FXR and neighboring histones, restores trimethylation of H3K4 and H3K9, and increases miR34a expression, thus reestablishing BA homeostasis. Consequently, NorUDCA restored liver regeneration in SIRT mice, which showed increased survival and hepatocyte proliferation. Furthermore, a leucine-enriched diet restored mammalian target of rapamycin (mTOR) activation, acetylation of FXR and histones, leading to an overall lower BA production through SHP-inhibition of Cyp7A1 and higher transport (BSEP) and detoxification (Sult2a1) leading to an improved liver regeneration. Finally, we found that human hepatocellular carcinoma (HCC) samples have increased presence of SIRT1, which correlated with the absence of FXR, suggesting its oncogenic potential.

CONCLUSION

We define SIRT1 as a key regulator of the regenerative response in the liver through posttranscriptional modifications that regulate the activity of FXR, histones, and mTOR. Moreover, our data suggest that SIRT1 contributes to liver tumorigenesis through dysregulation of BA homeostasis by persistent FXR deacetylation.

A histologic scoring system for prognosis of patients with alcoholic hepatitis

BACKGROUND & AIMS

There is no histologic classification system to determine prognoses of patients with alcoholic hepatitis (AH). We identified histologic features associated with disease severity and created a histologic scoring system to predict short-term (90-day) mortality.

METHODS

We analyzed data from 121 patients admitted to the Liver Unit (Hospital Clinic, Barcelona, Spain) from January 2000 to January 2008 with features of AH and developed a histologic scoring system to determine the risk of death using logistic regression. The system was tested and updated in a test set of 96 patients from 5 academic centers in the United States and Europe, and a semiquantitative scoring system called the Alcoholic Hepatitis Histologic Score (AHHS) was developed. The system was validated in an independent set of 109 patients. Interobserver agreement was evaluated by weighted κ statistical analysis.

RESULTS

The degree of fibrosis, degree of neutrophil infiltration, type of bilirubinostasis, and presence of megamitochondria were independently associated with 90-day mortality. We used these 4 parameters to develop the AHHS to identify patients with a low (0-3 points), moderate (4-5 points), or high (6-9 points) risk of death within 90 days (3%, 19%, and 51%, respectively; P < .0001). The AHHS estimated 90-day mortality in the training and test sets with an area under the receiver operating characteristic value of 0.77 (95% confidence interval, 0.71-0.83). Interrater agreement values were 0.65 for fibrosis, 0.86 for bilirubinostasis, 0.60 for neutrophil infiltration, and 0.46 for megamitochondria. Interestingly, the type of bilirubinostasis predicted the development of bacterial infections.

CONCLUSIONS

We identified histologic features associated with the severity of AH and developed a patient classification system that might be used in clinical decision making.

Disturbances in the murine hepatic circadian clock in alcohol-induced hepatic steatosis

To investigate the role of the circadian clock in the development of alcohol-induced fatty liver disease we examined livers of mice chronically alcohol-fed over 4-weeks that resulted in steatosis. Here we show time-of-day specific changes in expression of clock genes and clock-controlled genes, including those associated with lipid and bile acid regulation. Such changes were not observed following a 1-week alcohol treatment with no hepatic lipid accumulation. Real-time bioluminescence reporting of PERIOD2 protein expression suggests that these changes occur independently of the suprachiasmatic nucleus pacemaker. Further, we find profound time-of-day specific changes to the rhythmic synthesis/accumulation of triglycerides, cholesterol and bile acid, and the NAD/NADH ratio, processes that are under clock control. These results highlight not only that the circadian timekeeping system is disturbed in the alcohol-induced hepatic steatosis state, but also that the effects of alcohol upon the clock itself may actually contribute to the development of hepatic steatosis.

Activation of farnesoid X receptor attenuates hepatic injury in a murine model of alcoholic liver disease

Alcoholic liver disease (ALD) is a common cause of advanced liver disease, and considered as a major risk factor of morbidity and mortality worldwide. Hepatic cholestasis is a pathophysiological feature observed in all stages of ALD. The farnesoid X receptor (FXR) is a member of the nuclear hormone receptor superfamily, and plays an essential role in the regulation of bile acid, lipid and glucose homeostasis. However, the role of FXR in the pathogenesis and progression of ALD remains largely unknown. Mice were fed Lieber-DeCarli ethanol diet or an isocaloric control diet. We used a specific agonist of FXR WAY-362450 to study the effect of pharmacological activation of FXR in alcoholic liver disease. In this study, we demonstrated that FXR activity was impaired by chronic ethanol ingestion in a murine model of ALD. Activation of FXR by specific agonist WAY-362450 protected mice from the development of ALD. We also found that WAY-362450 treatment rescued FXR activity, suppressed ethanol-induced Cyp2e1 up-regulation and attenuated oxidative stress in liver. Our results highlight a key role of FXR in the modulation of ALD development, and propose specific FXR agonists for the treatment of ALD patients.

Intrahepatic cholestasis in common chronic liver diseases

BACKGROUND AND OBJECTIVE

Cholestasis represents the consequence of impaired bile formation and decrease in bile flow, generally classified as extra- and intrahepatic. Cholestasis is the pivotal hallmark of the so-called primary cholestatic liver diseases but may also emerge in other forms of chronic liver injury. The aim now was to summarise the current state of knowledge on intrahepatic cholestasis related to chronic liver diseases.

METHODS

For this overview on intrahepatic cholestasis in chronic liver disorders other than the 'classic' cholestatic liver diseases, selected references were retrieved by literature search in MEDLINE and textbooks were reviewed. All articles were selected that discussed pathophysiological and clinical aspects of intrahepatic cholestasis in the context of alcoholic liver disease, nonalcoholic fatty liver disease, chronic hepatitis B and C virus infections as well as drug-induced and granulomatous liver diseases. Titles referring to primary biliary cirrhosis and sclerosing cholangitis were excluded.

RESULTS AND CONCLUSIONS

Dependent on the aetiology, intrahepatic cholestasis is present at variable frequencies and in different disease stages in chronic liver diseases. Cholestasis secondary to chronic liver injury may denote a severe disease course and development of end-stage liver disease or specific disease variants. These findings indicate that 'secondary intrahepatic cholestasis' (SIC) can occur in the natural course of chronic liver diseases other than the primary cholestatic diseases, in particular in the setting of advanced disease progression.

Bile acids specifically increase hepatitis C virus RNA-replication

Background

Hepatitis C virus (HCV) patients with high serum levels of bile acids (BAs) respond poorly to IFN therapy. BAs have been shown to increase RNA-replication of genotype 1 but not genotype 2a replicons. Since BAs modulate lipid metabolism including lipoprotein secretion and as HCV depends on lipids and lipoproteins during RNA-replication, virus production and cell entry, BAs may affect multiple steps of the HCV life cycle. Therefore, we analyzed the influence of BAs on individual steps of virus replication.

Methods

We measured replication of subgenomic genotype (GT) 1b and 2a RNAs as well as full-length GT2a genomes in the presence of BAs using quantitative RT-PCR and luciferase assays. Cell entry was determined using HCV pseudoparticles (HCVpp). Virus assembly and release were quantified using a core-specific ELISA. Replicon chimeras were employed to characterize genotype-specific modulation of HCV by BAs. Lunet CD81/GFP-NLS-MAVS cells were used to determine infection of Con1 particles.

Results

BAs increased RNA-replication of GT1b replicons up to 10-fold but had no effect on subgenomic GT2a replicons both in Huh-7 and HuH6 cells. They did not increase viral RNA translation, virus assembly and release or cell entry. Lowering replication efficiency of GT2a replicons rendered them susceptible to stimulation by BAs. Moreover, replication of full length GT1b with or without replication enhancing mutations and GT2a genomes were also stimulated by BAs.

Conclusions

Bile acids specifically enhance RNA-replication. This is not limited to GT1, but also holds true for GT2a full length genomes and subgenomic replicons with low replication capacity. The increase of HCV replication by BAs may influence the efficacy of antiviral treatment in vivo and may improve replication of primary HCV genomes in cell culture.

Genetic variations in bile acid homeostasis are not overrepresented in alcoholic cirrhosis compared to patients with heavy alcohol abuse and absent liver disease

Increased serum bile salt levels have been associated to a single-nucleotide polymorphism in the bile salt export pump (BSEP; ABCB11) in several acquired cholestatic liver diseases but there is little evidence in alcoholic liver disease (ALD). Furthermore, a crosstalk between vitamin D and bile acid synthesis has recently been discovered. Whether this crosstalk has an influence on the course of ALD is unclear to date. Our aim was to analyse the role of genetic polymorphisms in BSEP and the vitamin D receptor gene (NR1I1) on the emergence of cirrhosis in patients with ALD. Therefore, 511 alcoholic patients (131 with cirrhosis and 380 without cirrhosis) underwent ABCB11 genotyping (rs2287622). Of these, 321 (131 with cirrhosis and 190 without cirrhosis) were also tested for NR1I1 polymorphisms (bat-haplotype: BsmI rs1544410, ApaI rs7975232 and TaqI rs731236). Frequencies of ABCB11 and NR1I1 genotypes and haplotypes were compared between alcoholic patients with and without cirrhosis and correlated to serum bile salt, bilirubin and aspartate aminotransferase levels in those with cirrhosis. Frequencies of ABCB11 and NR1I1 genotypes and haplotypes did not differ between the two subgroups and no significant association between genotypes/haplotypes and liver function tests could be determined for neither polymorphism. We conclude that ABCB11 and NR1I1 polymorphisms are obviously not associated with development of cirrhosis in patients with ALD.

Early liver biopsy, intraparenchymal cholestasis, and prognosis in patients with alcoholic steatohepatitis

Background

Alcoholic steatohepatitis (ASH) is a serious complication of alcoholic liver disease. The diagnosis of ASH requires the association of steatosis, evidence of hepatocellular injury with ballooning degeneration, and polynuclear neutrophil infiltration on liver biopsy. Whether these lesions, in addition to other histological features observed in liver tissue specimens, have prognostic significance is unclear.

Methods

We studied 163 patients (age 55 yrs [35-78], male/female 102/61) with recent, heavy (> 80 gr/day) alcohol intake, histologically-proven ASH (97% with underlying cirrhosis, Maddrey's score 39 [13-200], no sepsis), who had a liver biopsy performed 3 days [0-10] after hospital admission for clinical decompensation. A semi-quantitative evaluation of steatosis, hepatocellular damage, neutrophilic infiltration, periportal ductular reaction, intraparenchymal cholestasis, and iron deposits was performed by two pathologists. All patients with a Maddrey's score ≥ 32 received steroids. The outcome at 3 months was determined. Statistical analysis was performed using the Wilcoxon and Fisher's exact tests, Kaplan-Meier method, and the Cox proportional hazard model.

Results

43 patients died after 31 days [5-85] following biopsy. The 3-month survival rate was 74%. Mean kappa value for histological assessment by the two pathologists was excellent (0.92). Univariate analysis identified age, the Maddrey's score, the Pugh's score, the MELD score and parenchymal cholestasis, but not other histological features, as factors associated with 3-month mortality. At multivariate analysis, age (p = 0.029, OR 2.83 [1.11-7.2], intraparenchymal cholestasis (p = 0.001, OR 3.9 [1.96-7.8], and the Maddrey's score (p = 0.027, OR 3.93 [1.17-13.23] were independent predictors of outcome. Intraparenchymal cholestasis was more frequent in non survivors compared to survivors (70% versus 25%, p < 0.001). Serum bilirubin was higher in patients with severe compared to those with no or mild intraparenchymal cholestasis (238 [27-636] versus 69 [22-640] umol/l, p < 0.001).

Conclusions

In this large cohort of patients with histologically documented ASH early after admission and no sepsis, liver biopsy identified marked intraparenchymal cholestasis as an independent predictor of poor short term outcome together with age and the Maddrey's score. It may be hypothesized that incorporation of this particular variable into existing disease severity scores for ASH would improve their performance.

Compensatory induction of liver efflux transporters in response to ANIT-induced liver injury is impaired in FXR-null mice

Alpha-naphthyl isothiocyanate (ANIT) is a hepatotoxicant that produces acute intrahepatic cholestasis in rodents. Farnesoid X receptor (FXR) and pregnane X receptor (PXR) are two major bile acid sensors in liver. The purpose of this study was to characterize the regulation of hepatic transporters by FXR and PXR during ANIT-induced liver injury. Wild-type, FXR-null, and PXR-null mice were administered ANIT (75 mg/kg, po) and evaluated 48 h later for hepatotoxicity and messenger RNA (mRNA) expression of basolateral uptake (sodium taurocholate-cotransporting polypeptide, organic anion transporting polypeptide [Oatp] 1a1, Oatp1a4, Oatp1b2) and efflux transporters (organic solute transporter [Ost] alpha, Ostbeta, multidrug resistance-associated protein [Mrp] 3, Mrp4), as well as canalicular transporters (bile salt export pump [Bsep], Mrp2, multidrug resistance protein 2 [Mdr2], ATPase, class I, type 8B, member 1 [Atp8b1]). Livers from wild-type and PXR-null mice had comparable multifocal necrosis 48 h after ANIT. However, ANIT-treated FXR-null mice have fewer and smaller necrotic foci than wild-type mice but had scattered single-cell hepatocyte necrosis throughout the liver. Serum alanine transaminase, alkaline phosphatase (ALP), and direct bilirubin were increased in all genotypes, with higher ALP levels in FXR-null mice. Serum and liver unconjugated bile acids were higher in ANIT-treated FXR-null mice than the other two genotypes. ANIT induced mRNA expression of Mdr2, Bsep, and Atp8b1 in wild-type and PXR-null mice but failed to upregulate these genes in FXR-null mice. mRNA expression of uptake transporters declined in livers of all genotypes following ANIT treatment. ANIT increased Ostbeta and Mrp3 mRNA in livers of wild-type and PXR-null mice but did not alter Ostbeta mRNA in FXR-null mice. In conclusion, FXR deficiency enhances susceptibility of mice to ANIT-induced liver injury, likely a result of impaired induction of hepatobiliary efflux transporters and subsequent hepatic accumulation of unconjugated bile acids.

Increased serum gamma-glutamyl-transpeptidase concentration is associated with nonalcoholic steatosis and not with cholestasis in patients with chronic hepatitis C

BACKGROUND AND AIM

Increased pretreatment gamma-glutamyl-transpeptidase (gammaGT) is common in patients with chronic hepatitis C and with little or no alcohol consumption. The mechanism involved in this phenomenon is unclear, and the aim of this study was to investigate factors associated with increased gammaGT levels, specifically looking at the role of cholestasis that frequently accompanies hepatitis C.

METHODS

Fifty patients with chronic hepatitis C enrolled in two trials of antiviral treatment, 25 with normal and 25 with elevated pretreatment gammaGT levels, were retrospectively selected. In addition to the common liver function and virological tests, other values measured were serum bile acid concentration and composition by gas-chromatography as a sensitive index of cholestasis, and liver biopsy scores for cholestasis and steatosis in addition to siderosis, fibrosis and inflammation.

RESULTS

Total mean serum bile acid concentration was 11.6 +/- 1.4 micromol/L and 8.5 +/- 1.2 micromol/L (not significant) in patients with elevated and with normal gammaGT, respectively, and individual bile acid composition was similar in the two groups. By univariate analysis, serum gammaGT level was linearly related to total serum bile acid (P < 0.05) and to cholestasis score (P < 0.001) among other variables, but steatosis score (P < 0.001) and Knodell score (P < 0.04) were the only variables independently associated with elevated serum gammaGT level by multivariate analysis.

CONCLUSIONS

Increased serum gammaGT level in patients with chronic hepatitis C is associated with liver steatosis and fibrosis, and indicates more advanced liver disease rather than reflecting the cholestasis that often accompanies this condition.

Bile acid profiles by capillary electrophoresis in intrahepatic cholestasis of pregnancy

ICP (intrahepatic cholestasis of pregnancy) is characterized by pruritus and biochemical cholestasis, including raised SBAs (serum bile acids) and, usually, elevated aminotransferases levels. However, AHP (asymptomatic hypercholanaemia of pregnancy) is defined as the presence of total SBA levels above the cut-off value (11 μM) in healthy pregnant women, thus elevation of total SBAs do not necessarily reflect an ICP condition. The aim of the present study was to describe clinical, obstetric, perinatal and biochemical findings, as well as the SBA profile, in pregnant women studied in the third trimester of pregnancy in order to define characteristic patterns of individual bile acids that enable women with ICP to be distinguished from AHP and healthy pregnancies. Free and conjugated ursodeoxycholic (UDCA), cholic (CA), lithocholic (LCA), deoxycholic (DCA) and chenodeoxycholic (CDCA) acids were evaluated by CE (capillary electrophoresis) in 41 patients (15 of them simultaneously by HPLC), in 30 healthy pregnant women and in 10 non-pregnant women. A highly significant correlation between CE and HPLC for total SBAs (r=0.990) and for individual SBAs was found. Normal pregnant women had higher total SBA levels than non-pregnant women (due to an increase in taurine-conjugated dihydroxy SBAs). Women with ICP had higher levels of total SBAs, the free/conjugated ratio, LCA, CA, CDCA and DCA than normal pregnant women. Newborns from women with ICP had lower birth weight and gestational age. Women with AHP had higher levels of conjugated dihydroxy SBAs than normocholanaemic patients, without any evidence of a clinical difference. In conclusion, the present study has shown a clear difference in SBA profiles between ICP and normal pregnancies (including AHP), involving a shift towards a characteristic hydrophobic composition in women with ICP.

A randomized controlled trial of ursodeoxycholic acid in patients with alcohol-induced cirrhosis and jaundice

The aim of our multicenter study was to assess the efficacy of ursodeoxycholic acid (UDCA) on the survival of patients with alcohol-induced cirrhosis and jaundice. We included patients with histologically proven alcohol-induced cirrhosis and serum bilirubin >50 micromol/L. After randomization, patients received either UDCA (13-15 mg/kg/d) or a placebo for 6 months. Two hundred twenty-six patients (113 in each group) were included in 24 centers. There were 139 men and 87 women, mean age of 50.3 years. Seventy-four percent had associated alcohol-induced hepatitis, and 24% received a corticosteroid therapy. At inclusion, the 2 groups were comparable for the main clinical and biologic parameters, but serum bilirubin was higher in the UDCA group than in the placebo group (163 micromol/L vs. 145 micromol/L, P <.03). The percentage of patients lost at follow-up or who resumed their alcoholism during the study was comparable in the 2 groups. During the study, 55 patients died, 35 in the UDCA group and 20 in the placebo group. In the intention to treat analysis, the probability of survival at 6 months (Kaplan-Meier method) was lower in the UDCA than in the P group (69% vs. 82%, respectively; P =.04, log-rank test). After adjustment on the bilirubin level at entry (Cox model), the independent predictive value of the treatment group did not reach the statistical level (RR = 1.64, CI 0.85-2.85; P =.077). In conclusion, UDCA administered at the dose recommended in primary biliary cirrhosis has no beneficial effect on the 6-month survival of patients with severe alcohol-induced cirrhosis. An inappropriate dosage of UDCA cannot be excluded as an explanation for the lack of therapeutic benefit.

Cholestasis and alcoholic liver disease

Histologic cholestasis and clinical jaundice may be seen in all stages of alcoholic liver disease. In rare cases, isolated cholestasis without significant steatosis, hepatitis, or cirrhosis is identified in an alcoholic patient. The mechanisms of ethanol-induced cholestasis are not well studied but may involve compression of intrahepatic biliary radicals or interference with basolateral uptake and intracellular transport of bile acids. In the evaluation of the jaundiced alcoholic patient, clinical, biochemical, and radiologic data are usually sufficient to distinguish alcohol-induced liver disease from extrahepatic biliary obstruction. In cases where the diagnosis is not readily apparent, more invasive studies such as liver biopsy or ERCP may be necessary. The risk of these invasive studies is directly related to the degree of underlying hepatic dysfunction.