Medical treatment of primary sclerosing cholangitis: a role for novel bile acids and other (post-)transcriptional modulators?

Hepatic Nuclear Receptors in Cholestasis-to-Cholangiocarcinoma Pathology

Cholestasis, characterized by impaired bile flow, is associated with an increased risk of cholangiocarcinoma (CCA), a malignancy originating from the biliary epithelium and hepatocytes. Hepatic nuclear receptors (NRs) are pivotal in regulating bile acid and metabolic homeostasis, and their dysregulation is implicated in cholestatic liver diseases and the progression of liver cancer. This review elucidates the role of various hepatic NRs in the pathogenesis of cholestasis-to-CCA progression. It explores their impact on bile acid metabolism as well as their interactions with other signaling pathways implicated in CCA development. Additionally, it introduces available murine models of cholestasis/primary sclerosing cholangitis leading to CCA and discusses the clinical potential of targeting hepatic NRs as a promising approach for the prevention and treatment of cholestatic liver diseases and CCA. Understanding the complex interplay between hepatic NRs and cholestasis-to-CCA pathology holds promise for the development of novel preventive and therapeutic strategies for this devastating disease.

Pediatric Autoimmune or Primary Sclerosing Cholangitis: Metronidazole Effectiveness on Biochemical Data, Bile Acid Profile, and Gut Microbiota: A Pilot Study

Objectives

Autoimmune hepatitis and primary sclerosing cholangitis (PSC) can both be present, resulting in autoimmune sclerosing cholangitis (ASC). PSC physiopathology could be based on the cross-talk between gut microbiota and bile acids (BAs); antibiotics are an innovative therapy. This pilot study assesses metronidazole (MTZ)'s effectiveness in ASC or PSC patients according to the stage of the disease, and its effects on biochemical parameters, BA profiles, and gut microbiota.

Methods

ASC or PSC patients from Cliniques universitaires Saint-Luc's pediatric hepato-gastroenterology division were enrolled retrospectively and prospectively; both datasets were merged. MTZ was administered over at least 14 days on top of standard treatment (ursodeoxycholic acid, azathioprine, and steroids). Fecal and blood samples were collected before (T0) and at MTZ day 14 (T14). Sustained biochemical remission was defined by the reduction of transaminases (AST and ALT), gamma-glutamyl transferase (GGT), and CRP until 12 months post-MTZ.

Results

A total of 18 patients (mean age, 13.2 ± 4.5 years) were enrolled (13 ASC and 5 PSC), and divided in remission or relapse patients. CRP, AST, ALT, and GGT levels decreased post-MTZ in both groups (excepting GGT in relapse patients), with decreases between T0 and T14 being significant for AST and ALT. Relapse patients were older (P = 0.0351) and in late-disease stage, with mainly large-duct PSC (P = 0.0466). In remission patients, the mean plasma relative abundance of hydrophilic BA increased by +6.3% (P = 0.0391) after MTZ. Neither at baseline nor T14, there were significant differences in gut microbiota recorded.

Conclusion

These data are likely indicative of long-term benefits following MTZ therapy at early-stage ASC or PSC, with increased hydrophilic BA abundance. Multicenter prospective studies are needed.

The neglected biliary mucus and its phosphatidylcholine content: a putative player in pathogenesis of primary cholangitis-a narrative review article

Primary sclerosing cholangitis (PSC) is a rare progressive cholangitis resulting in cirrhosis and cholangiocellular carcinoma. The pathogenesis is unclear and an effective medical therapy is not available. It is highly associated to ulcerative colitis for which recently a disturbance of the tight junction (TJ) barrier has been claimed as etiologic feature. Genetic mouse models with intestinal TJ disruption showed a defective transport of phosphatidylcholine (PC) to intestinal mucus. Consequently, an ulcerative colitis phenotype developed. In the present study we evaluate whether there is also a paracellular transport of PC through TJ to the apical side of cholangiocytes. As in ulcerative colitis, a TJ defect could lead to deficient PC in biliary mucus. It would impair the protective barrier against aggressive bile acids in bile. Indeed with polarized biliary tumor cells a vectorial transport of PC from basal to luminal side was demonstrated using a transwell culture system. PC was not taken up by the cells but moved paracellularly via TJ to the apical side driven by luminal HCO₃- generated by the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) and the anion exchange protein 2 (AE2). If such a TJ-mediated PC translocation to the apical surface of cholangiocytes could be disrupted in a genetic mouse model, a PSC phenotype would be expected. With such an experimental model functional operative therapies can be evaluated. We propose that disruption of TJ mediated paracellular transport of PC to the apical side of cholangiocytes could lead to biliary mucus PC depletion. This may be a pathogenetic factor for development of PSC.

G-protein-coupled bile acid receptor plays a key role in bile acid metabolism and fasting-induced hepatic steatosis in mice

Bile acids are signaling molecules that play a critical role in regulation of hepatic metabolic homeostasis by activating nuclear farnesoid X receptor (Fxr) and membrane G-protein-coupled receptor (Takeda G-protein-coupled receptor 5; Tgr5). The role of FXR in regulation of bile acid synthesis and hepatic metabolism has been studied extensively. However, the role of TGR5 in hepatic metabolism has not been explored. The liver plays a central role in lipid metabolism, and impaired response to fasting and feeding contributes to steatosis and nonalcoholic fatty liver and obesity. We have performed a detailed analysis of gallbladder bile acid and lipid metabolism in Tgr5^-/- mice in both free-fed and fasted conditions. Lipid profiles of serum, liver and adipose tissues, bile acid composition, energy metabolism, and messenger RNA and protein expression of the genes involved in lipid metabolism were analyzed. Results showed that deficiency of the Tgr5 gene in mice alleviated fasting-induced hepatic lipid accumulation. Expression of liver oxysterol 7α-hydroxylase in the alternative bile acid synthesis pathway was reduced. Analysis of gallbladder bile acid composition showed marked increase of taurocholic acid and decrease of tauro-α and β-muricholic acid in Tgr5^-/- mice. Tgr5^-/- mice had increased hepatic fatty acid oxidation rate and decreased hepatic fatty acid uptake. Interestingly, fasting induction of fibroblast growth factor 21 in liver was attenuated. In addition, fasted Tgr5^-/- mice had increased activation of hepatic growth hormone-signal transducer and activator of transcription 5 (GH-Stat5) signaling compared to wild-type mice.

CONCLUSION

TGR5 may play a role in determining bile acid composition and in fasting-induced hepatic steatosis through a novel mechanism involving activation of the GH-Stat5 signaling pathway. (Hepatology 2017;65:813-827).

Doppler Ultrasound and Transient Elastography in Liver Transplant Patients for Noninvasive Evaluation of Liver Fibrosis in Comparison with Histology: A Prospective Observational Study

BACKGROUND AND AIM

Accurate quantification of progressive liver disease is essential for therapeutic decisions and follow-up for patients who underwent liver transplantation. To evaluate the quality of noninvasive assessment of liver fibrosis in these patients, we compared Doppler ultrasound of the hepatic blood vessels as well as transient elastography (TE, FibroScan(®)) with liver biopsy following transplantation.

METHODS

We performed Doppler ultrasound of the hepatic veins, hepatic artery, and portal vein as well as a TE in 48 patients who underwent liver transplantation 12 months ago. Hepatic venous flow was evaluated by determination of the resistance index (HVRI) of the right hepatic vein. Doppler and TE results were compared with histopathologic workup of a 12-month protocol liver biopsy after transplantation.

RESULTS

HVRI showed a high reliability in predicting liver fibrosis stage FII or higher (AUROC of 0.99 ± 0.001 for FII or higher, the HVRI < 1.05 with a sensitivity and specificity of 100 and 91.43 %) compared to histopathologic workup (Desmet's score) and was comparable to TE analysis. Both HVRI and TE differed significantly in no or minimal fibrosis versus FII or higher (p < 0.001). In contrast, portal vein and hepatic artery did not show significant changes in blood flow in our study population.

CONCLUSIONS

Hepatic vein flow resistance index is a valuable tool in noninvasive evaluation of liver fibrosis in liver transplantation follow-up predicting FII or higher and might help reducing the number of protocol biopsies needed.

Efficacy of obeticholic acid in patients with primary biliary cirrhosis and inadequate response to ursodeoxycholic acid

BACKGROUND & AIMS

We evaluated the efficacy and safety of obeticholic acid (OCA, α-ethylchenodeoxycholic acid) in a randomized controlled trial of patients with primary biliary cirrhosis who had an inadequate response to ursodeoxycholic acid therapy.

METHODS

We performed a double-blind study of 165 patients with primary biliary cirrhosis (95% women) and levels of alkaline phosphatase (ALP) 1.5- to 10-fold the upper limit of normal. Patients were randomly assigned to groups given 10 mg, 25 mg, or 50 mg doses of OCA or placebo, once daily for 3 months. Patients maintained their existing dose of ursodeoxycholic acid throughout the study. The primary outcome was change in level of ALP from baseline (day 0) until the end of the study (day 85 or early termination). We also performed an open-label extension of the trial in which 78 patients were enrolled and 61 completed the first year.

RESULTS

OCA was superior to placebo in achieving the primary end point. Subjects given OCA had statistically significant relative reductions in mean ALP from baseline to the end of the study (P < .0001 all OCA groups vs placebo). Levels of ALP decreased 21%-25% on average from baseline in the OCA groups and 3% in the placebo group. Sixty-nine percent (68 of 99) of patients given OCA had at least a 20% reduction in ALP compared with 8% (3 of 37) of patients given placebo (P < .0003). Among secondary end points, levels of γ-glutamyl transpeptidase decreased 48%-63%, on average, among subjects given OCA, vs a 7% decrease in the group given placebo; levels of alanine aminotransferase decreased 21%-35% on average among subjects given OCA vs none of the patients given placebo. Pruritus was the principal adverse event; incidence values in the OCA 10 mg, 25 mg, and 50 mg groups were 47% (not significantly different), 87% (P < .0003), and 80% (P < .006), respectively, vs 50% in the placebo group. In the extension study, levels of ALP continued to decrease to a mean level of 202 ± 11 U/L after 12 months vs 285 ± 15 U/L at baseline.

CONCLUSIONS

Daily doses of OCA, ranging from 10 to 50 mg, significantly reduced levels of ALP, γ-glutamyl transpeptidase, and alanine aminotransferase, compared with placebo, in patients with primary biliary cirrhosis who had inadequate responses to ursodeoxycholic acid. The incidence and severity of pruritus were lowest among patients who received 10 mg/d OCA. Biochemical responses to OCA were maintained in a 12-month open-label extension trial. ClinicalTrials.gov ID: NCT00550862.

Soluble intracellular adhesion molecule, M30 and M65 as serum markers of disease activity and prognosis in cholestatic liver diseases

AIM

Hepatic apoptosis is involved in the pathogenesis of immune-mediated liver diseases such as autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC). The aim of our study was to quantify distinct markers of apoptosis in sera of patients with AIH, PBC and PSC, and to evaluate correlation with markers of disease activity and prognosis.

METHODS

Sera of patients with AIH, PBC and PSC, and of healthy controls were collected and distinct cell death markers were quantified using a bead-based multiplex enzyme linked immunosorbent assay (soluble intracellular adhesion molecule [sICAM], macrophage migration inhibitory factor [MIF], soluble Fas [sFas], plasminogen activator inhibitor 1 [PAI-1]) or single enzyme-linked immunosorbent assays (DNAse, M30, M65).

RESULTS

In comparison with healthy controls, the apoptotic markers sFas, sICAM (only in PSC patients), M30 and the cell death marker M65 were substantially elevated in sera of patients with immune-mediated liver diseases, whereas DNAse activity was reduced. Interestingly, patients with advanced PSC presented with higher levels of sICAM, M30 and M65 than patients with mild PSC. Regression analysis revealed correlations between serum levels of sICAM, M30 and M65 with the Mayo Risk Score for PSC, and of M65 with the Mayo Risk Score for PBC.

CONCLUSION

Concentrations of the serum markers of apoptosis sFas and M30 and of the marker of total cell death M65 are elevated in patients with immune-mediated liver diseases, whereas activity of DNAse is reduced. In patients with PSC, sICAM, M30 and M65 may serve as indicators for disease activity and prognosis.

Differential effects of norUDCA and UDCA in obstructive cholestasis in mice

BACKGROUND & AIMS

The quest for effective drugs to treat cholangiopathies led to the development of norUDCA previously shown to have potent choleretic effects and to heal cholangiopathy in Abcb4 knockout (Abcb4(-/-)) mice. Its mother compound UDCA had detrimental effects in common bile duct ligated (CBDL) mice, presumably related to its choleretic effects. norUDCA choleretic effects may therefore raise safety concerns when used in cholangiopathies with biliary obstruction. We therefore aimed at comparing the effects of UDCA and norUDCA in clear-cut obstructive cholestasis.

METHODS

0.5% UDCA- or norUDCA-fed wild type and Abcb4(-/-) mice were subjected to CBDL or selective bile duct ligation (SBDL) and compared to controls with regard to liver injury. Bile flow, bile composition, and biliary manometry were compared in UDCA-fed, norUDCA-fed and control mice. Toxicity of UDCA and norUDCA was compared in vitro.

RESULTS

Compared to UDCA, liver injury in CBDL mice was significantly lower in almost all norUDCA groups. In SBDL mice, only UDCA induced bile infarcts in the ligated lobes, whereas norUDCA even ameliorated liver injury. In vitro, UDCA induced cellular ATP depletion and was significantly more toxic than norUDCA in HepG2 cells, mouse bile duct epithelial cells, and primary human hepatocytes.

CONCLUSIONS

Compared to norUDCA, UDCA is significantly more toxic in CBDL mice. norUDCA, in contrast to UDCA, significantly ameliorates liver injury in SBDL mice. Our findings uncover profound differences in metabolism and therapeutic mechanisms of both bile acids with important clinical consequences.

Effect of ursodeoxycholic acid on bile acid profiles and intestinal detoxification machinery in primary biliary cirrhosis and health

BACKGROUND & AIMS

Ursodeoxycholic acid (UDCA) exerts anticholestatic, antifibrotic and antiproliferative effects in primary biliary cirrhosis (PBC) via mechanisms not yet fully understood. Its adequate biliary enrichment is considered mandatory for therapeutic efficacy. However, precise determination of biliary enrichment of UDCA is not possible in clinical practice. Therefore, we investigated (i) the relationship between biliary enrichment and plasma pharmacokinetics of UDCA, (ii) the effect of UDCA on plasma and biliary bile acid composition and conjugation patterns, and (iii) on the intestinal detoxification machinery in patients with PBC and healthy controls.

METHODS

In 11 PBC patients and 11 matched healthy subjects, cystic bile and duodenal tissue were collected before and after 3 weeks of administration of UDCA (15 mg/kg/day). Extensive pharmacokinetic profiling of bile acids was performed. The effect of UDCA on the intestinal detoxification machinery was studied by quantitative PCR and Western blotting.

RESULTS

The relative fraction of UDCA and its conjugates in plasma at trough level[x] correlated with their biliary enrichment[y] (r=0.73, p=0.0001, y=3.65+0.49x). Taurine conjugates of the major hydrophobic bile acid, chenodeoxycholic acid, were more prominent in bile of PBC patients than in that of healthy controls. Biliary bile acid conjugation patterns normalized after treatment with UDCA. UDCA induced duodenal expression of key export pumps, BCRP and P-glycoprotein.

CONCLUSIONS

Biliary and trough plasma enrichment of UDCA are closely correlated in PBC and health. Taurine conjugation may represent an adaptive mechanism in PBC against chenodeoxycholic acid-mediated bile duct damage. UDCA may stabilize small intestinal detoxification by upregulation of efflux pumps.

Complement factor C5 deficiency significantly delays the progression of biliary fibrosis in bile duct-ligated mice

Fibrogenesis represents the universal response of the liver to chronic liver injury. Complement factor C5 has been linked to fibrosis in murine toxic liver injury and human chronic hepatitis C. C5 may also play a central role in chronic cholestatic disorders, since the BA receptor FXR has been characterized as an activator of the C3 gene. We aimed to investigate, whether C5 deficiency is able to prevent biliary fibrosis in the mouse bile-duct-ligation model. BDL for 1-4 weeks was performed in either Hc(0)/Hc(0) mice (deficient for C5) or WT controls. BA levels were measured by RIA. Histological examination included H&E, sirius-red and immunohistochemistry. mRNA expression was quantified by RT-PCR. Protein expression levels were determined by Western blotting or ELISA. Enzymatic MMP-activity was analysed by zymography. One week BDL leads to fibrosis in WT (F2.0 ± 0), while it is almost absent in Hc(0)/Hc(0) mice (F0.5 ± 0.5). No differences in fibrosis can be detected at week-4. Together with delayed fibrogenesis at week-1, fibrotic markers are decreased in Hc(0)/Hc(0) mice. Expression of the inflammatory cytokine TNF-α is decreased in Hc(0)/Hc(0) mice. In parallel C5 deficiency leads to an attenuated peribiliary infiltration of CD45(+) cells in fibrotic areas together with decreased MMP-9 expression and gelatinase activity. The present study proves a functional role of C5 during biliary fibrogenesis. C5 deficiency leads to attenuated inflammation and normalized MMP-9 activity concomitantly with a significant reduction of fibrosis. C5 appears to be an attractive target for future therapeutic intervention in chronic cholestatic liver disease.

TUDCA slows retinal degeneration in two different mouse models of retinitis pigmentosa and prevents obesity in Bardet-Biedl syndrome type 1 mice

PURPOSE

To evaluate and compare the protective effect of tauroursodeoxycholic acid (TUDCA) on photoreceptor degeneration in different models of retinal degeneration (RD) in mice.

METHODS

Bbs(M390R/M390R) mice were injected subcutaneously twice a week, from P40 to P120, and rd10 mice were injected every 3 days from P6 to P38 with TUDCA or vehicle (0.15 M NaHCO(3)). Rd1 and rd16 mice were injected daily from P6 to P30 with TUDCA or vehicle. Retinal structure and function were determined at multiple time points by electroretinography (ERG), optical coherence tomography (OCT), and histology.

RESULTS

The amplitude of ERG b-waves was significantly higher in TUDCA-treated Bbs1 and rd10 animals than in controls. Retinal thickness on OCT was slightly greater in treated Bbs1 animals than in the controls. Histologically, outer segments were preserved, and the outer nuclear layer was significantly thicker in the treated Bbs1 and rd10 mice than in the controls. Bbs1(M390R/M390R) mice developed less obesity than the control Bbs1(M390R/M390R) while receiving TUDCA. The Rd1 and rd16 mice showed no improvement with TUDCA treatment, and the rd1 mice did not have normal weight gain during treatment.

CONCLUSIONS

TUDCA treatment preserved ERG b-waves and the outer nuclear layer in Bbs1(M390R/M390R) mice, and prevented obesity assessed at P120. TUDCA treatment preserved ERG b-waves and the outer nuclear layer in the rd10 mice to P30. TUDCA is a prime candidate for treatment of humans with retinal degeneration, especially those with Bardet-Biedl syndrome, whom it may help not only with the vision loss, but with the debilitating obesity as well.

Medical and endoscopic therapy of primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is a rare cholestatic liver disease mainly affecting young male patients. PSC is characterised by chronic inflammation and fibrotic strictures of the intra- and extrahepatic biliary system, which eventually lead to cholestasis and biliary cirrhosis. However, the clinical course remains very variable. As the aetiology remains unknown, the development of a causative treatment is challenging and today no specific medical therapy is available. Ursodeoxycholic acid has been widely used for the treatment of PSC, but improved only biochemistry and/or symptoms in low- or medium dosages and is probably harmful in higher dosages. Other drugs such as immunosuppressive, antifibrotic or antibiotic agents have not been proven to be effective in large clinical trials. The endoscopic therapy encompasses balloon-dilatation and/or stenting of strictures, relieves clinical symptoms and improves a cholestatic enzyme profile. However, endoscopic therapy is limited to patients in advanced stages of PSC with biliary obstruction.

Primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is a chronic liver condition which may affect both intra and extrahepatic biliary tree. Etiology of PSC remains to be fully elucidated but genetic, autoimmune, inflammatory and possibly infective factors could all contribute to its development. More than two-thirds of patients are males and the most commonly associated condition is an inflammatory bowel disease which occurs in up to 70% of affected subjects. Endoscopic cholangiopancreatography (ERCP) and magnetic resonanse cholangiopancreatography (MRCP) remain a gold standard in the diagnosis of this condition. No curative treatment of PSC exists and a proportion of patients who develop liver failure or suffer from recurrent episodes of cholangitis requires liver transplantation. PSC is associated with increased risk of malignancies, in particular cholangiocarcinoma which may arise in 12% of patients. The main aim of this chapter is to review the current knowledge on pathogenesis and clinical aspects of PSC as well as its associated malignancies.

Review article: colorectal neoplasia in patients with primary sclerosing cholangitis and inflammatory bowel disease

BACKGROUND

Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease strongly associated with inflammatory bowel disease (IBD). IBD patients diagnosed with PSC have an increased risk of colorectal dysplasia and cancer.

AIMS

To review the available evidence regarding colorectal neoplasia epidemiology, preventive strategies and outcomes in patients with PSC and IBD, and to advance some hypotheses regarding possible mechanisms involved in cancer pathogenesis in these patients.

METHODS

A PubMed search was conducted for the English language publications with predetermined search criteria. Reference lists from studies selected were manually searched to identify further relevant reports. Relevant manuscripts considering colorectal neoplasia in patients with PSC-IBD were selected.

RESULTS

Primary sclerosing cholangitis increases the risk of colorectal neoplasia in patients with ulcerative colitis; fewer data are available for Crohn's disease. PSC-IBD patients tend to be younger at diagnosis of IBD and at diagnosis of colorectal cancer. Colorectal cancer in PSC-IBD patients predominates in the right colon. The increased risk of neoplasia is maintained after liver transplant and proctocolectomy. The role of ursodeoxycholic acid as a chemopreventive agent is controversial. The mechanisms underlying increased risk of colorectal neoplasia in these patients remain unknown.

CONCLUSIONS

A more comprehensive understanding of the mechanisms involved in colorectal neoplasia development in PSC-IBD patients is needed. Until then, early cancer detection through enrolment in surveillance programmes is the only available strategy to decrease cancer risk.

Bile acids for primary sclerosing cholangitis

BACKGROUND

Primary sclerosing cholangitis is a progressive chronic cholestatic liver disease that usually leads to the development of cirrhosis. Studies evaluating bile acids in the treatment of primary sclerosing cholangitis have shown a potential benefit of their use. However, no influence on patients survival and disease outcome has yet been proven.

OBJECTIVES

To assess the beneficial and harmful effects of bile acids for patients with primary sclerosing cholangitis.

SEARCH STRATEGY

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, The Cochrane Library, MEDLINE, EMBASE and Science Citation Index Expanded generally from inception through to October 2010.

SELECTION CRITERIA

Randomised clinical trials comparing any dose of bile acids or duration of treatment versus placebo, no intervention, or another intervention were included irrespective of blinding, language, or publication status.

DATA COLLECTION AND ANALYSIS

Two authors extracted data independently. We evaluated the risk of bias of the trials using prespecified domains. We performed the meta-analysis according to the intention-to-treat principle. We presented outcomes as relative risks (RR) or mean differences (MD), both with 95% confidence intervals (CI).

MAIN RESULTS

Eight trials evaluated ursodeoxycholic acid versus placebo or no intervention (592 patients). The eight randomised clinical trials have a high risk of bias. Patients were treated for three months to six years (median three years). The dosage of ursodeoxycholic acid used in the trials ranged from low (10 mg/kg body weight/day) to high (28 to 30 mg/kg body weight/day). Ursodeoxycholic acid did not significantly reduce the risk of death (RR 1.00; 95% CI 0.46 to 2.20); treatment failure including liver transplantation, varices, ascites, and encephalopathy (RR 1.22; 95% CI 0.91 to 1.64); liver histological deterioration (RR 0.89; 95% CI 0.45 to 1.74); or liver cholangiographic deterioration (RR 0.60; 95% CI 0.23 to 1.57). Ursodeoxycholic acid significantly improved serum bilirubin (MD -14.6 µmol/litre; 95% CI -18.7 to -10.6), alkaline phosphatases (MD -506 IU/litre; 95% CI -583 to -430), aspartate aminotransferase (MD -46 IU/litre; 95% CI -77 to -16), and gamma-glutamyltranspeptidase (MD -260 IU/litre; 95% CI -315 to -205), but not albumin (MD -0.20 g/litre; 95% CI -1.91 to 1.50). Ursodeoxycholic acid was safe and well tolerated by patients with primary sclerosing cholangitis.

AUTHORS' CONCLUSIONS

We did not find enough evidence to support or refute the use of bile acids in the treatment of primary sclerosing cholangitis. However, bile acids seem to lead to a significant improvement in liver biochemistry. Therefore, more randomised trials are needed before any of the bile acids can be recommended for this indication.

Treatment options for primary sclerosing cholangitis

Primary sclerosing cholangitis is a cholestatic liver disease characterized by inflammation and fibrosis of intra-/extrahepatic bile ducts, leading to multifocal strictures. Primary sclerosing cholangitis exhibits a progressive course resulting in cirrhosis and the need for liver transplantation over a median period of 12 years. The disease is frequently associated with inflammatory bowel disease and carries an increased risk of colorectal cancer and cholangiocarcinoma. Despite extensive research, there is currently no effective medical treatment. Multiple drugs are shown to be ineffective in halting disease progression, including ursodeoxycholic acid, the most widely evaluated drug. High-dose ursodeoxycholic acid (28-30 mg/kg/day) was recently shown to increase the adverse events rate. Endoscopic or radiological dilatation of a 'dominant' stricture may lead to symptomatic and biochemical improvement. However, liver transplantation is the only life-prolonging treatment for patients with end-stage disease. Studies with promising drugs, such as antibiotics, antifibrotic agents and bile acid derivatives, are eagerly awaited.

Crosstalk of liver, bile ducts and the gut

A complex interplay of liver, bile ducts, and the gut critically determines functioning of these organs in health and disease. Biochemical and physiological aspects of their interaction and the role of inflammatory cells, cytokines, bile acids, visceral hormones, neuropeptides and other messengers in the pathogenesis of model immune-mediated hepatobiliary disorders are discussed in the actual issue of Clinical Reviews in Allergy and Immunology. Potential molecular targets for future therapeutic approaches are also addressed.