Chronic cholestatic diseases

Novel insight into mechanisms of cholestatic liver injury

Cholestasis results in a buildup of bile acids in serum and in hepatocytes. Early studies into the mechanisms of cholestatic liver injury strongly implicated bile acid-induced apoptosis as the major cause of hepatocellular injury. Recent work has focused both on the role of bile acids in cell signaling as well as the role of sterile inflammation in the pathophysiology. Advances in modern analytical methodology have allowed for more accurate measuring of bile acid concentrations in serum, liver, and bile to very low levels of detection. Interestingly, toxic bile acid levels are seemingly far lower than previously hypothesized. The initial hypothesis has been based largely upon the exposure of μmol/L concentrations of toxic bile acids and bile salts to primary hepatocytes in cell culture, the possibility that in vivo bile acid concentrations may be far lower than the observed in vitro toxicity has far reaching implications in the mechanism of injury. This review will focus on both how different bile acids and different bile acid concentrations can affect hepatocytes during cholestasis, and additionally provide insight into how these data support recent hypotheses that cholestatic liver injury may not occur through direct bile acid-induced apoptosis, but may involve largely inflammatory cell-mediated liver cell necrosis.

Approach to a patient with elevated serum alkaline phosphatase

Cholestasis develops either from a defect in bile synthesis, impairment in bile secretion, or obstruction to bile flow, and is characterized by an elevated serum alkaline phosphatase and gamma-glutamyltransferase disproportionate to elevation of aminotransferase enzymes. Key elements to the diagnostic workup include visualization of the biliary tree by cholangiography and evaluation of liver histology. The hope is that recent advances in understanding the genetic factors and immune mechanisms involved in the pathogenesis of cholestasis will lead to newer therapeutic interventions in the treatment of these diseases.

Urinary tract infection as a risk factor for autoimmune liver disease: from bench to bedside

Autoimmune liver diseases include autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC), and primary sclerosing cholangitis. A variety of environmental and genetic risk factors have been associated with these conditions. Recurrent urinary tract infections (rUTI) have been strongly associated with PBC, and to a lesser extent with AIH. These observations were initially based on the observation of significant bacteriuria in female patients with PBC. Larger epidemiological studies demonstrated that there was indeed a strong correlation between recurrent UTI and PBC. AIH has not been linked to recurrent UTI in epidemiological studies; however treatment of UTI with nitrofurantoin can induce AIH. As Escherichia coli is the most prevalent organism isolated in women with UTI, it has been suggested that molecular mimicry between microbial and human PDC-E2 (the main autoantigenic target in PBC) epitopes may explain the link between UTI and PBC. Multiple studies have demonstrated molecular mimicry and immunological cross-reactivity involving microbial and self-antigen mimics. This review will examine the literature surrounding UTI and autoimmune liver disease. This will include case reports and epidemiological studies, as well as experimental data.

Ductopenia related liver sarcoidosis

Sarcoidosis is a systemic granulomatous disease which may involve many organs. In approximately 95% of patients there is liver involvement, with noncaseating hepatic granulomas occurring in 21 to 99% of patients with sarcoidosis. Liver involvement is usually asymptomatic and limited to mild to moderate abnormalities in liver biochemistry. The occurrence of jaundice in sarcoidosis is rare; extensive imaging procedures and the examination of liver biopsies permit a precise diagnostic. Ductopenia associated with sarcoidosis has been reported in less than 20 cases and can lead to biliary cirrhosis and liver- related death. We report here on a case of ductopenia-related sarcoidosis in which primary biliary cirrhosis and extrahepatic cholestasis have been carefully excluded. The patient follow up was 8 years. Although ursodesoxycholic acid appears to improve liver biochemistry it does not preclude the rapid occurrence of extensive fibrosis. A review of the literature of reported cases of ductopenia related to sarcoidosis is provided.

Comparison of simplified score with the revised original score for the diagnosis of autoimmune hepatitis: a new or a complementary diagnostic score?

BACKGROUND AND AIMS

The International Autoimmune Hepatitis Group developed a simplified score for autoimmune hepatitis. We assessed this "new scoring system" and compared it with the International Autoimmune Hepatitis Group original revised score.

METHODS

502 patients were evaluated namely, 428 had liver diseases of various etiology [hepatitis B (n=109), hepatitis C (n=100), hepatitis D (n=4), alcoholic liver disease (n=28), non-alcoholic fatty liver disease (n=55), autoimmune cholestatic diseases (n=77), liver disorders of undefined origin (n=32) and miscellaneous hepatic disorders (n=23)], 13 had autoimmune hepatitis/overlap syndromes, 18 had autoimmune hepatitis/concurrent with other liver diseases and 43 had autoimmune hepatitis.

RESULTS

The specificity of the simplified score was similar to that of the revised score (97% vs. 97.9%). The sensitivity in unmasking autoimmune hepatitis in autoimmune hepatitis/overlap syndromes was also similar in both systems (53.8% and 61.5%). However, the sensitivity for autoimmune hepatitis diagnosis in autoimmune hepatitis patients with concurrent liver disorders was lower by the new score (p=0.001). Liver biopsy proved to be the only independent factor for unmasking autoimmune hepatitis component among patients (p=0.003).

CONCLUSION

The simplified score is a reliable and simple tool for excluding autoimmune hepatitis. However, both systems cannot unmask autoimmune hepatitis component efficiently in autoimmune hepatitis patients with concurrent autoimmune or non-autoimmune liver diseases. This study also strongly reiterates the importance of liver biopsy in the work-up of patients.

Primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is an idiopathic chronic autoimmune liver disease that primarily affects women. It is believed that the aetiology for PBC is a combination between environmental triggers in genetically vulnerable persons. The diagnosis for PBC is made when two of the three criteria are fulfilled and they are: (1) biochemical evidence of cholestatic liver disease for at least 6 month's duration; (2) anti-mitochondrial antibody (AMA) positivity; and (3) histologic features of PBC on liver biopsy. Ursodeoxycholic acid (UDCA) is the only FDA-approved medical treatment for PBC and should be administered at a recommended dose of 13-15 mg/kg/day. Unfortunately despite adequate dosing of UDCA, approximately one-third of patients does not respond adequately and may require liver transplantation. Future studies are necessary to elucidate the role of environmental exposures and overall genetic impact not only in the development of PBC, but on disease progression and variable clinical response to therapy.

Darbepoetin-α inhibits the perpetuation of necro-inflammation and delays the progression of cholestatic fibrosis in mice

Biliary obstruction and cholestasis result in hepatocellular necro-inflammation and lead to the development of liver fibrosis. The objective of this study was to analyze whether the multiple tissue-protective properties of erythropoietin are salutary in an experimental model of liver fibrosis. For this purpose, C57BL/6J mice underwent common bile duct ligation (BDL) and were treated with either darbepoetin-α (10 μg/kg i.p.) or physiological saline every third day, beginning 24 h after BDL. Mice were killed at 2, 5, 14, and 28 days after BDL. Beside hematological parameters, markers of inflammation and fibrosis were assessed histomorphometrically and immunohistochemically as well as by quantitative real-time PCR. In addition, a 7-week survival study was performed. BDL provoked cholestatic hepatitis characterized by biliary infarcts with accumulation of macrophages followed by marked collagen deposition and increased expression of profibrotic gene transcripts. Darbepoetin-α treatment significantly diminished the area of focal necrosis, reduced the infiltration of macrophages, decreased levels of profibrotic genes, and lowered collagen deposition. Moreover, darbepoetin-α significantly reduced systemic anemia caused by BDL. Finally, darbepoetin-α treatment significantly prolonged the survival time after BDL. This study suggests that darbepoetin-α, which is a clinically well-established substance, might be used as an efficient therapeutic option for patients with chronic cholestatic liver disease.

Glucocorticosteroids for primary sclerosing cholangitis

BACKGROUND

Primary sclerosing cholangitis is a chronic cholestatic disease of intrahepatic and extrahepatic biliary ducts, characterised by chronic periductal inflammation and sclerosis of the ducts, which results in segmental stenoses of bile ducts, cholestasis, fibrosis, and ultimately, liver cirrhosis. Patients with primary sclerosing cholangitis are at higher risk of cholangiocarcinoma as well as of colonic neoplasia, since primary sclerosing cholangitis is associated with inflammatory bowel disease in more than 80% of the patients. Several therapeutic modalities have been proposed for primary sclerosing cholangitis, like ursodeoxycholic acid, glucocorticosteroids, and immunomodulatory agents, but none has been successful in reversing the process of the disease. To date, liver transplantation is the only definite therapeutic solution for patients with advanced primary sclerosing cholangitis with liver cirrhosis.

OBJECTIVES

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

SEARCH STRATEGY

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, The Cochrane Central Register of Controlled Trials in The Cochrane Library, MEDLINE, EMBASE, and LILACS from their inception until September 2009, as well as reference lists.

SELECTION CRITERIA

Randomised clinical trials comparing any dose or duration of glucocorticosteroids versus placebo, no intervention, or other immunosuppressive agents. We included trials irrespective of language, blinding, or publication status.

DATA COLLECTION AND ANALYSIS

Authors extracted data independently and assessed the methodological quality by the generation of the allocation sequence, allocation concealment, double blinding, follow-up, incomplete outcome data reporting, selective reporting, baseline imbalance, and early stopping. The results of the meta-analyses were presented as relative risks (RR) or mean difference (MD), both with 95% confidence intervals (CI). The primary outcome measures were mortality and liver-related morbidity.

MAIN RESULTS

Two randomised clinical trials were eligible for inclusion. One trial compared biliary lavage with hydrocortisone versus saline in 17 patients. Hydrocortisone tended to increase adverse events (pancreatitis, cholangitis with septicaemia, paranoid ideas, fluid retention) (RR 3.43, 95% CI 0.51 to 22.9) and had no cholangiographic improvement, which led to termination of the trial. The other trial compared budesonide versus prednisone in 18 patients. Patients had statistically significant higher serum bilirubin concentration after treatment with prednisone compared with budesonide (MD 10.4 micromol/litre, 95% CI 1.16 to 19.64 micromol/litre). No other statistically significant effects on clinical or biochemical outcomes were reported on any of the evaluated interventions.

AUTHORS' CONCLUSIONS

There is no evidence to support or refute peroral glucocorticosteroids for patients with primary sclerosing cholangitis. The intrabiliary application of corticosteroids via nasobiliary tube seems to induce severe adverse effects.

Immune-mediated liver diseases: programmed cell death ligands and circulating apoptotic markers

Primary biliary cirrhosis, primary sclerosing cholangitis and autoimmune hepatitis are the three major immune-mediated liver diseases. The etiologies of primary biliary cirrhosis, primary sclerosing cholangitis and autoimmune hepatitis are largely unknown, but seem to be influenced by genetic and environmental factors. Autoantibodies can be found in nearly all patients with primary sclerosing cholangitis and autoimmune hepatitis, and in the vast majority of patients with primary sclerosing cholangitis. In addition, autoimmune hepatitis is associated with high concentrations of serum globulins. Enhanced liver cell death by apoptosis has been described in all of these liver diseases, although the precise mechanisms remain unclear. In general, apoptosis can be initiated via an extrinsic pathway that is triggered by engagement of death receptors on the cell surface, or via an intrinsic pathway that is induced by mitochondrial injury and is influenced by members of the Bcl-2 family. In both pathways, effector caspases are finally activated that cleave and degrade cell structures, resulting in the release of apoptotic products into the circulation. New diagnostic tests can detect these apoptotic markers and programmed cell death ligands such as Fas and Fas-ligands, nucleosomes, caspases, cytokeratin fragments, macrophage migration inhibitory factor, soluble intracellular adhesion molecule, natural killer cells group 2D and programmed death ligands. Several of these markers have been found to be altered in tissue and/or blood of immune-mediated liver diseases, some also in nonimmune-mediated liver diseases. Beyond their potential usefulness as additional diagnostic markers, they may be valuable for the estimation of disease severity and therapy monitoring. This review summarizes current knowledge on apoptotic mechanisms, death receptor ligands and circulating apoptotic markers in immune-mediated liver diseases.

Absence of glycochenodeoxycholic acid (GCDCA) in human bile is an indication of cholestasis: a 1H MRS study

The utility of (1)H MR spectroscopy in detecting chronic cholestasis has been investigated. The amide proton region of the (1)H MR spectrum of human bile plays a major role in differentiating cholestatic (Ch) patterns from the normal ones. Bile obtained from normal bile ducts contains both taurine and glycine conjugates of bile acids--cholic acid (CA), chenodeoxycholic acid (CDCA), and deoxycholic acid (DCA). Absence of a glycine-conjugated bile acid glycochenodeoxycholic acid (GCDCA) has been observed in bile samples obtained from primary sclerosing cholangitis (PSC) patients. A total of 32 patients with various hepatobiliary diseases were included in the study. Twenty-one patients had PSC and 11 had normal cholangiograms. One PSC patient was excluded from the study because of a bad spectrum. Seventeen out of the 20 PSC patients showed an absence of GCDCA in their (1)H MR spectrum of bile. Six of the 11 reference patients with normal cholangiogram also showed spectra similar to those of PSC, indicating the possibility of cholestasis. DQF-COSY and TOCSY experiments performed on bile samples from PSC patients also revealed absence of phosphatidylcholine (PC) in some of the bile samples, suggesting possible damage to the cholangiocytes by the toxic bile. These observations suggest that analysis of human bile by (1)H MRS could be of value in the diagnosis of chronic Ch liver disorders.

Dietary glycine blunts liver injury after bile duct ligation in rats

AIM: To investigate the effects of (dietary) glycine against oxidant-induced injury caused by bile duct ligation (BDL).

METHODS: Either a diet containing 5% glycine or a standard diet was fed to male Sprague-Dawley (SD) rats. Three days later, BDL or sham-operation was performed. Rats were sacrificed 1 to 3 d after BDL. The influence of deoxycholic acid (DCA) in the presence or absence of glycine on liver cells was determined by measurement of calcium and chloride influx in cultivated Kupffer cells and lactate dehydrogenase (LDH) activity was determined in the supernatant of cultivated hepatocytes.

RESULTS: Serum alanine transaminase levels increased to about 600 U/L 1 d after BDL. However, enzyme release was blunted by about two third in rats receiving glycine. Release of the alkaline phosphatase and aspartate aminotransferase was also blocked significantly in the group fed glycine. Focal necrosis was observed 2 d after BDL. Glycine partially blocked the histopathological changes. Incubation of Kupffer cells with DCA led to increased intracellular calcium that could be blocked by incubation with glycine. However, systemic blockage of Kupffer cells with gadolinium chloride had no effects on transaminase release. Incubation of isolated hepatocytes with DCA led to a significant release of LDH after 4 h. This release was largely blocked when incubation with glycine was performed.

CONCLUSION: These data indicate that glycine significantly decreased liver injury, most likely by a direct effect on hepatocytes. Kupffer cells do not appear to play an important role in the pathological changes caused by cholestasis.

NIM811 (N-methyl-4-isoleucine cyclosporine), a mitochondrial permeability transition inhibitor, attenuates cholestatic liver injury but not fibrosis in mice

Cholestasis causes hepatocyte death, possibly because of mitochondrial injury. This study investigated whether NIM811 (N-methyl-4-isoleucine cyclosporine), an inhibitor of the mitochondrial permeability transition (MPT), attenuates cholestatic liver injury in vivo. Cholestasis was induced in mice by bile duct ligation (BDL). NIM811 was gavaged (20 mg/kg) before BDL and daily (10 mg/kg) afterward. Mitochondrial depolarization, cell death, and MPT onset were assessed by intravital confocal/multiphoton microscopy of rhodamine 123, propidium iodide, and calcein. After BDL, serum alanine aminotransferase (ALT), hepatic necrosis, and apoptosis all increased. NIM811 decreased ALT, necrosis, and apoptosis by 60 to 86%. In vehicle-treated mice at 6 h after BDL, viable hepatocytes with depolarized mitochondria were 18/high-power field (hpf), and nonviable cells were approximately 1/hpf, showing that depolarization preceded necrosis. Calcein entered mitochondria after BDL, indicating MPT onset in vivo. NIM811 decreased depolarization by 72%, prevented calcein entry into mitochondria, and blocked release of cytochrome c. Hepatic tumor necrosis factor alpha, transforming growth factor-beta1, procollagen alpha1(I) mRNA, alpha-smooth muscle actin, and Sirius red staining for collagen increased after BDL but were not different in vehicle- and NIM811-treated mice. Taken together, NIM811 decreased cholestatic necrosis and apoptosis but did not block fibrosis, indicating that the MPT plays an important role in cholestatic cell death in vivo.

Multiple cyclin kinase inhibitors promote bile acid-induced apoptosis and autophagy in primary hepatocytes via p53-CD95-dependent signaling

Previously, using primary hepatocytes residing in early G1 phase, we demonstrated that expression of the cyclin-dependent kinase (CDK) inhibitor protein p21Cip-1/WAF1/mda6 (p21) enhanced the toxicity of deoxycholic acid (DCA) + MEK1/2 inhibitor. This study examined the mechanisms regulating this apoptotic process. Overexpression of p21 or p27(Kip-1) (p27) enhanced DCA + MEK1/2 inhibitor toxicity in primary hepatocytes that was dependent on expression of acidic sphingomyelinase and CD95. Overexpression of p21 suppressed MDM2, elevated p53 levels, and enhanced CD95, BAX, NOXA, and PUMA expression; knockdown of BAX/NOXA/PUMA reduced CDK inhibitor-stimulated cell killing. Parallel to cell death processes, overexpression of p21 or p27 profoundly enhanced DCA + MEK1/2 inhibitor-induced expression of ATG5 and GRP78/BiP and phosphorylation of PKR-like endoplasmic reticulum kinase (PERK) and eIF2alpha, and it increased the numbers of vesicles containing a transfected LC3-GFP construct. Incubation of cells with 3-methyladenine or knockdown of ATG5 suppressed DCA + MEK1/2 inhibitor-induced LC3-GFP vesicularization and enhanced DCA + MEK1/2 inhibitor-induced toxicity. Expression of dominant negative PERK blocked DCA + MEK1/2 inhibitor-induced expression of ATG5, GRP78/BiP, and eIF2alpha phosphorylation and prevented LC3-GFP vesicularization. Knock-out or knockdown of p53 or CD95 abolished DCA + MEK1/2 inhibitor-induced PERK phosphorylation and prevented LC3-GFP vesicularization. Thus, CDK inhibitors suppress MDM2 levels and enhance p53 expression that facilitates bile acid-induced, ceramide-dependent CD95 activation to induce both apoptosis and autophagy in primary hepatocytes.

Long-term follow-up of antimitochondrial antibody-positive autoimmune hepatitis

Antimitochondrial antibodies (AMAs) are the serological hallmark for primary biliary cirrhosis (PBC). When AMAs are detected in patients with chronic hepatitis, they negatively impact on the autoimmune hepatitis (AIH) scoring system. The purpose of this study was to determine if AMAs detected in the sera of patients with overt AIH have clinical or pathological significance. All patients with a clinicopathologic diagnosis of AIH from one center were reviewed. Only those meeting the criteria for probable or definite AIH according to the International Autoimmune Hepatitis Group were included. Patients found to be consistently AMA-positive via enzyme-linked immunosorbent assay (ELISA) for pyruvate dehydrogenase complex E2 subunit were reviewed in detail. Fifteen of 126 patients with typical features of AIH (pretreatment AIH score >10) had detectable AMAs in serum. None had any histologic features suggestive of PBC. None had detectable anti-liver-kidney-microsomal antibodies. Of these 15 patients, all have remained persistently AMA-positive via ELISA. All 15 patients have been followed long-term, and their clinical course remained typical for AIH. No bile duct damage typical of PBC was seen on initial or follow-up liver biopsies.

CONCLUSION

Patients with overt AIH who test positive for AMAs at initial presentation and are treated with corticosteroid therapy have shown no clinical or histologic evidence of PBC despite the continued detection of AMAs over a follow-up of up to 27 years.

Overlap syndromes among autoimmune liver diseases

The three major immune disorders of the liver are autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC). Variant forms of these diseases are generally called overlap syndromes, although there has been no standardized definition. Patients with overlap syndromes present with both hepatitic and cholestatic serum liver tests and have histological features of AIH and PBC or PSC. The AIH-PBC overlap syndrome is the most common form, affecting almost 10% of adults with AIH or PBC. Single cases of AIH and autoimmune cholangitis (AMA-negative PBC) overlap syndrome have also been reported. The AIH-PSC overlap syndrome is predominantly found in children, adolescents and young adults with AIH or PSC. Interestingly, transitions from one autoimmune to another have also been reported in a minority of patients, especially transitions from PBC to AIH-PBC overlap syndrome. Overlap syndromes show a progressive course towards liver cirrhosis and liver failure without treatment. Therapy for overlap syndromes is empiric, since controlled trials are not available in these rare disorders. Anticholestatic therapy with ursodeoxycholic acid is usually combined with immunosuppressive therapy with corticosteroids and/or azathioprine in both AIH-PBC and AIH-PSC overlap syndromes. In end-stage disease, liver transplantation is the treatment of choice.

Effects of low fat and babassu fat diets on nutritional status in obstructive cholestasis in young rats

PURPOSE: To test the effects of a low fat diet compared with a babassu fat diet on nutritional status in obstructive cholestasis in young rats. METHODS: We submitted 40 rats in 4 groups of 10 animals each from P21 (21st postnatal day) to P49 to two of the following treatments: bile duct ligation or sham operation and low fat diet (corn oil supplying 4.5% of the total amount of energy) or babassu fat diet (this fat supplying 32.7% and corn oil supplying 1.7% of the total amount of energy). Weight gain from P25 to P49 every 4 days was measured. The Verhulst's growth function was fitted to these values of weight gain. Growth velocity and acceleration at each moment were estimated using the same equation. Total food and energy intake from P21 to P49, energy utilization rate (EUR) from P25 to P49 and fat absorption rate (FAR) and nitrogen balance (NB) from P42 to P49 were measured. Two Way ANOVA and the S.N.K. test for multiple paired comparisons were employed to study the effects of cholestasis and those of the diets and their interaction (p<0.05) on those variables. RESULTS: In cholestatic animals, a higher growth velocity at P45, a higher growth acceleration at P41 and P45, a greater EUR, a greater FAR and a greater NB, were found with the low fat diet as compared with the babassu fat diet. CONCLUSION: A low fat diet lessens the growth restriction brought about by cholestasis and allows for an improved dietary energy utilization and a better protein balance than the babassu fat diet.

Primary biliary cirrhosis in female subjects with sicca-associated antibodies

The aim of this study is to clarify the time course of primary biliary cirrhosis (PBC) in subjects possessing anticentromere antibodies (ACA), anti-Ro, and/or anti-La antibodies, and who used alkaline phosphatase (ALP) as a serological marker for PBC. Female subjects (n = 165), who had at least one of ACA, anti-Ro, and/or anti-La, were enrolled in this study. Groups A (ACA alone, n = 44), B (anti-Ro alone, n = 54), E (anti-Ro and anti-La, n = 52), and DFG (ACA with anti-Ro and/or anti-La, n = 14) were analyzed. Healthy females (n = 65) were used as a control. The frequencies of the PBC in groups A (13.6%) and DFG (14.3%) were higher than those in groups B (1.9%) and E (0.0%). The ALP levels increased with age in groups A and DFG and slightly increased with age in groups B and C, and the control group. After correcting for age by analysis of covariance, a comparison of ALP levels among the groups not having anti-M(2) was as follows: group A falling dots group DFG > group B falling dots group E falling dots the control group. The subjects with ACA might thus have PBC more frequently than either those with anti-Ro and/or anti-La, or the control subjects.

17-Allylamino-17-demethoxygeldanamycin enhances the lethality of deoxycholic acid in primary rodent hepatocytes and established cell lines

Ansamycin antibiotics that target heat shock protein 90 function are being developed as anticancer agents but are also known to be dose limiting in patients due to hepatotoxicity. Herein, to better understand how the normal tissue toxicity of geldanamycins could be ameliorated to improve the therapeutic index of these agents, we examined the interactions of 17-allylamino-17-demethoxygeldanamycin (17AAG) and the secondary bile acid deoxycholic acid (DCA) in hepatocytes and fibroblasts. DCA and 17AAG interacted in a greater than additive fashion to cause hepatocyte cell death within 2 to 6 h of coadministration. As single agents DCA, but not 17AAG, enhanced the activity of extracellular signal-regulated kinase 1/2, AKT, c-Jun NH(2)-terminal kinase 1/2 (JNK1/2), and p38 mitogen-activated protein kinase (MAPK). Combined exposure of cells to DCA and 17AAG further enhanced JNK1/2 and p38 MAPK activity. Inhibition of JNK1/2 or p38 MAPK, but not activator protein-1, suppressed the lethality of 17AAG and of 17AAG and DCA. Constitutive activation of AKT, but not MAPK/extracellular signal-regulated kinase kinase 1/2, suppressed 17AAG- and DCA-induced cell killing and reduced activation of JNK1/2. DCA and 17AAG exposure promoted association of BAX with mitochondria, and functional inhibition of BAX or caspase-9, but not of BID and caspase-8, suppressed 17AAG and DCA lethality. DCA and 17AAG interacted in a greater than additive fashion to promote and prolong the generation of reactive oxygen species (ROS). ROS-quenching agents, inhibition of mitochondrial function, expression of dominant-negative thioredoxin reductase, or expression of dominant-negative apoptosis signaling kinase 1 suppressed JNK1/2 and p38 MAPK activation and reduced cell killing after 17AAG and DCA exposure. The potentiation of DCA-induced ROS production by 17AAG was abolished by Ca(2+) chelation and ROS generation, and cell killing following 17AAG and DCA treatment was abolished in cells lacking expression of PKR-like endoplasmic reticulum kinase. Thus, DCA and 17AAG interact to stimulate Ca(2+)-dependent and PKR-like endoplasmic reticulum kinase-dependent ROS production; high levels of ROS promote intense activation of the p38 MAPK and JNK1/2 pathways that signal to activate the intrinsic apoptosis pathway.

Expression of bile acid synthesis and detoxification enzymes and the alternative bile acid efflux pump MRP4 in patients with primary biliary cirrhosis

BACKGROUND

Bile acid synthesis, transport and metabolism are markedly altered in experimental cholestasis. Whether such coordinated regulation exists in human cholestatic diseases is unclear. We therefore investigated expression of genes for bile acid synthesis, detoxification and alternative basolateral export and regulatory nuclear factors in primary biliary cirrhosis (PBC).

MATERIAL/METHODS

Hepatic CYP7A1, CYP27A1, CYP8B1 (bile acid synthesis), CYP3A4 (hydroxylation), SULT2A1 (sulphation), UGT2B4/2B7 (glucuronidation), MRP4 (basolateral export), farnesoid X receptor (FXR), retinoid X receptor (RXR), short heterodimer partner (SHP), hepatocyte nuclear factor 1alpha (HNF1alpha) and HNF4alpha expression was determined in 11 patients with late-stage PBC and this was compared with non-cholestatic controls.

RESULTS

CYP7A1 mRNA was repressed in PBC to 10-20% of controls, while CYP27 and CYP8B1 mRNA remained unchanged. SULT2A1, UGT2B4/2B7 and CYP3A4 mRNA levels were unaltered or only mildly reduced in PBC. MRP4 protein levels were induced three-fold in PBC, whereas mRNA levels remained unchanged. Expression levels of FXR, RXR, SHP, PXR, CAR, HNF1alpha and HNF4alpha were moderately reduced in PBC without reaching statistical significance.

SUMMARY/CONCLUSIONS

Repression of bile acid synthesis and induction of basolateral bile acid export may represent adaptive mechanisms to limit bile acid burden in chronic cholestasis. As these changes do not sufficiently counteract cholestatic liver damage, future therapeutic strategies should aim at stimulation of bile acid detoxification pathways.

Ghrelin alleviates biliary obstruction-induced chronic hepatic injury in rats

BACKGROUND

Reactive oxygen species and oxidative stress are implicated in hepatic stellate cell activation and liver fibrosis, which are initiated by recruitment of inflammatory cells and by activation of cytokines.

OBJECTIVE

The possible anti-oxidant and anti-inflammatory effects of ghrelin were evaluated in a hepatic fibrosis model in rats with bile duct ligation (BDL).

METHODS

Under anesthesia, bile ducts of Sprague Dawley rats were ligated, and half of the rats were subcutaneously administered with ghrelin (10 ng/kg/day) and the rest with saline for 28 days. Sham-operated control groups were administered saline or ghrelin. On the 28th day of the study, rats were decapitated and malondialdehyde (MDA) content--an index of lipid peroxidation, and myeloperoxidase (MPO) activity--an index of neutrophil infiltration--were determined in the liver tissues. Oxidant-induced tissue fibrosis was determined by collagen contents, while the hepatic injury was analyzed microscopically. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) levels and lactate dehydrogenase (LDH) levels were determined to assess liver function and tissue damage, respectively. Pro-inflammatory cytokines; TNF-alpha, IL-1beta and IL-6 were also assayed in plasma samples.

RESULTS

In the saline-treated BDL group, hepatic MDA levels, MPO activity and collagen content were increased (p<0.001), suggesting oxidative organ damage, as confirmed histologically. In the ghrelin-treated BDL group, however, all of the oxidant responses were reversed significantly (p<0.05-p<0.001). Serum AST, ALT, LDH levels, and cytokines were elevated in the BDL group as compared to the control group, while this increase was significantly decreased by ghrelin treatment.

CONCLUSION

Owing to the anti-inflammatory and anti-oxidant effect as demonstrated in our study, it is possible to speculate that exogenously administered ghrelin may possess an antifibrotic effect against biliary obstruction-induced liver fibrosis. Thus, it seems likely that ghrelin may be of potential therapeutic value in protecting the liver fibrosis and oxidative injury due to biliary obstruction.

Heme oxygenase-1 overexpression increases liver injury after bile duct ligation in rats

AIM: To investigate the effects of heme oxygenase-1 (HO-1) against oxidant-induced injury caused by bile duct ligation (BDL).

METHODS: Either cobalt protoporphyrin (CoPP), a HO-1 inducer, or saline were injected intraperitoneally in male SD-rats. Three days later, BDL or sham-operations were performed. Rats were sacrificed 3 wk after BDL and livers were harvested for histology. Fibrosis was evaluated by sirius red staining and image analysis. Alpha-smooth muscular actin, which indicates activation of stellate cells, was detected by immunohistochemical staining, and cytokine and collagen-Iα (Col-Iα) mRNA expression was detected using RNase protection assays.

RESULTS: Serum alanine transaminase increased 8-fold above normal levels one day after BDL. Surprisingly, enzyme release was not reduced in rats receiving CoPP. Liver fibrosis was evaluated 3 wk after BDL and the sirius red-positive area was found to be increased to about 7.8%. However, in CoPP pretreated rats sirius red-positive areas were increased to about 11.7% after BDL. Collagen-Iα and TGF-β mRNA increased significantly by BDL. Again, this effect was increased by HO-1 overexpression.

CONCLUSION: Hepatic fibrosis due to BDL is not reduced by the HO-1 inducer CoPP. In contrast, HO-1 overexpression increases liver injury in rats under conditions of experimental chronic cholestasis.

The revised international autoimmune hepatitis score in chronic liver diseases including autoimmune hepatitis/overlap syndromes and autoimmune hepatitis with concurrent other liver disorders

BACKGROUND

We conducted a study in order to determine the usefulness and diagnostic value of International Autoimmune Hepatitis Group (IAHG) score in non-autoimmune hepatitis (AIH) hepatic disorders as well as in AIH/overlap syndromes and in cases with coexistence of AIH and other liver diseases.

METHODS

We applied the IAHG score in 423 patients with liver diseases excluding patients with AIH, AIH/overlap syndromes and AIH with concurrent other liver disease namely, patients with chronic hepatitis B (n = 109), chronic hepatitis C (n = 95), chronic hepatitis D (n = 4), alchoholic liver disease (n = 28), non-alcoholic fatty liver disease (n = 55), autoimmune cholestatic liver diseases (n = 77), liver disorders of undefined origin (n = 32) and with miscellaneous hepatic disorders (n = 23). 24 patients with AIH associated with any kind of liver disorder including 10 patients with AIH/overlap syndromes and 14 AIH with concurrent other liver disease were also investigated. 43 patients with AIH consisted the control group.

RESULTS

The specificity of the score was 98.1% while the sensitivity in unmasking AIH in patients with either AIH/overlap syndromes or AIH with concurrent other liver diseases was only 50% and 78.6%. In the binary logistic regression model, the presence of other autoimmune diseases (p < 0.001), the total histological score (p < 0.001) and positivity for autoantibodies (p < 0.05) were identified as independent predictors for the presnce of AIH/ovea syndromes o AI with concurren other liver diseass.

CONCLUSION

The IAHG scoring system has very good specificity for excluding AIH in patients with chronic liver diseases but not that sensitivity in order to unmask AIH/overlap syndromes or AIH with concurrent other liver diseases. The presence of other autoimmune diseases or autoantibody markers in the absence of hepatitis viral markers should alarm physicians for the possible presence of AIH either as "pure" AIH or in association with other liver disorders (AIH/overlap syndromes or AIH with concurrent other liver diseases). Under these conditions, liver histology seems essential and it must always be included in the work up of hepatic patients.

Grape seed extract reduces oxidative stress and fibrosis in experimental biliary obstruction

BACKGROUND AND AIM

The aim of this study was to assess the protective effect of grape seed extract (GSE) against oxidative liver injury and fibrosis induced by biliary obstruction in rats.

METHODS

Wistar albino rats were divided into four groups; control (C), GSE-treated, bile duct ligated (BDL), and BDL and GSE-treated (BDL + GSE) groups. GSE was administered at a dose of 50 mg/kg a day orally for 28 days. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) levels were determined to assess liver function and tissue damage, respectively. Tumor necrosis factor-alpha (TNF-alpha) and antioxidant capacity (AOC) were assayed in plasma samples. Liver tissues were taken for determination of the hepatic malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity and collagen content. Production of reactive oxidants was monitored by chemiluminescence (CL) assay.

RESULTS

Serum AST, ALT, LDH and plasma TNF-alpha were elevated in the BDL group as compared to the control group and were significantly decreased with GSE treatment. Plasma AOC and hepatic GSH level, depressed by BDL, was elevated back to the control level in the GSE-treated BDL group. Increases in tissue MDA level, MPO activity and collagen content due to BDL were also attenuated by GSE treatment. Furthermore, luminol and lucigenin CL values in the BDL group increased dramatically compared to the control and were reduced by GSE treatment.

DISCUSSION

These results suggest that GSE protects the liver from oxidative damage following bile duct ligation in rats. This effect possibly involves the inhibition of neutrophil infiltration and lipid peroxidation; thus, restoration of oxidant and antioxidant status in the tissue.

Erdosteine treatment attenuates oxidative stress and fibrosis in experimental biliary obstruction

Oxidative stress, in particular lipid peroxidation, induces collagen synthesis and causes fibrosis. The aim of this study was to assess the antioxidant and antifibrotic effects of erdosteine on liver fibrosis induced by biliary obstruction in rats. Liver fibrosis was induced in Wistar albino rats by bile duct ligation (BDL). Erdosteine (10 mg/kg, orally) or saline was administered for 28 days. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) levels were determined to assess liver functions and tissue damage, respectively. Pro-inflammatory cytokines, TNF-alpha, IL-1beta and IL-6 and antioxidant capacity (AOC) were assayed in plasma samples. Liver tissues were taken for determination of malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity and collagen content. Production of reactive oxidants was monitored by chemiluminescence assay. Serum AST, ALT, LDH, and plasma cytokines were elevated in the BDL group as compared to controls and were significantly decreased by erdosteine treatment. Hepatic GSH level and plasma AOC, depressed by BDL, were elevated back to control level with erdosteine treatment. Furthermore, hepatic luminol and lucigenin chemiluminescence (CL), MDA level, MPO activity and collagen content in BDL group increased dramatically compared to control and reduced by erdosteine treatment. Since erdosteine administration alleviated the BDL-induced oxidative injury of the liver and improved the hepatic functions, it seems likely that erdosteine with its antioxidant and antifibrotic properties, may be of potential therapeutic value in protecting the liver fibrosis and oxidative injury due to biliary obstruction.

Risk factors associated with HCV infection in semi-rural areas of central Greece

BACKGROUND

Hepatitis C virus (HCV) appears to be endemic in most parts of the world, but there is considerable geographic variation. In order to assess the geographic distribution of HCV in Thessaly, in central Greece, we conducted a retrospective study in HCV-infected patients attending the Academic Liver Unit of Thessaly University from 1999 to 2003. We also investigated whether variation among regions could be attributed to differences in risk factors.

METHODS

We evaluated the records of 309 HCV patients whose origin and/or residence was in Thessaly. To identify risk factors that were independently associated with the place of birth and/or residence, adjusted odds ratios (OR) were calculated by logistic regression analysis. We also studied the medical records of 150 HCV-negative patients from the same areas in order to evaluate whether there are differences in risk factors reported by HCV-positive and HCV-negative patients.

RESULTS

We found three municipalities with a high HCV frequency. The use of non-disposable, multiple-use glass syringes for medical purposes in the past was the only potential risk factor more frequently identified in these areas than in other places (OR=2.3; p<0.05). This risk factor was significantly (p<0.001) associated with older age of the infected patients.

CONCLUSIONS

This study shows that the spread of HCV in the three regions may have occurred several years ago as a result of the use of multiple-use glass syringes. Differences in prevalence rates among different age groups, as well as among different areas, indicate the need for extensive studies to determine HCV epidemiology and to develop appropriate prevention programs.

Detection of Helicobacter species in chronic liver disease and chronic inflammatory bowel disease

AIM

To study the association between helicobacters and chronic liver diseases and chronic inflammatory bowel diseases.

PATIENTS AND METHODS

Thirty-two patients with various chronic liver diseases and 137 patients with inflammatory bowel disease were enrolled. Antibodies to H. pylori, H. hepaticus, H. bilis, and H. pullorum were measured by enzyme immunoassay (EIA), and sera positive in a non-pylori helicobacter EIA were further examined by immunoblot assay. Detection of Helicobacter DNA in liver biopsies was done by denaturating gradient gel electrophoresis of PCR products (PCR-DGGE) and DNA sequence analysis.

RESULTS

Six inflammatory bowel disease patients, four with ulcerative colitis and two with Crohn's disease, and one liver disease patient with autoimmune cholangitis had antibodies to non-pylori helicobacters by an immunoblot assay. Four immunoblot assay-negative patients, three with autoimmune and one with non-autoimmune liver disease, had Helicobacter DNA in liver biopsies; three of the polymerase chain reaction (PCR) products were closely related to non-pylori helicobacters.

CONCLUSION

Evidence for non-pylori helicobacters was scant in Finnish patients with inflammatory bowel disease or chronic but not end stage liver disease. We cannot, however, rule out their role in these diseases.

Heterogeneity of the intrahepatic biliary epithelium

The objectives of this review are to outline the recent findings related to the morphological heterogeneity of the biliary epithelium and the heterogeneous pathophysiological responses of different sized bile ducts to liver gastrointestinal hormones and peptides and liver injury/toxins with changes in apoptotic, proliferative and secretory activities. The knowledge of biliary function is rapidly increasing because of the recognition that biliary epithelial cells (cholangiocytes) are the targets of human cholangiopathies, which are characterized by proliferation/damage of bile ducts within a small range of sizes. The unique anatomy, morphology, innervation and vascularization of the biliary epithelium are consistent with function of cholangiocytes within different regions of the biliary tree. The in vivo models [e.g., bile duct ligation (BDL), partial hepatectomy, feeding of bile acids, carbon tetrachloride (CCl₄) or α-naphthylisothiocyanate (ANIT)] and the in vivo experimental tools [e.g., freshly isolated small and large cholangiocytes or intrahepatic bile duct units (IBDU) and primary cultures of small and large murine cholangiocytes] have allowed us to demonstrate the morphological and functional heterogeneity of the intrahepatic biliary epithelium. These models demonstrated the differential secretory activities and the heterogeneous apoptotic and proliferative responses of different sized ducts. Similar to animal models of cholangiocyte proliferation/injury restricted to specific sized ducts, in human liver diseases bile duct damage predominates specific sized bile ducts. Future studies related to the functional heterogeneity of the intrahepatic biliary epithelium may disclose new pathophysiological treatments for patients with cholangiopathies.

[Anicteric cholestasis: imaging and diagnostic strategy]

Cholestasis is due to abnormal biliary secretion, from hepatic or extra hepatic causes. The diagnostic strategy of anicteric cholestasis will be discussed, defining hepatic biologic abnormalities, and the role and sequence of imaging techniques based on clinical and biological findings. Main causes will be emphasized and illustrated with different radiological techniques (US, CT and MRI).

Medical treatment of primary biliary cirrhosis and primary sclerosing cholangitis

Chronic cholestasis is the main feature of primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC), the most common chronic cholestatic liver diseases in adults. Although the etiology of both diseases remains poorly understood, auto-immune processes appear to be important, particularly in PBC. PBC and PSC usually slowly progress to cirrhosis,liver failure, and death, unless liver transplantation is performed. Ursodeoxycholic acid(UDCA), a hydrophilic dihydroxy bile acid, is the only drug currently approved for the treatment of patients with PBC and is also used in patients with PSC. In addition to UDCA, patients with PSC should be referred to endoscopic dilatation of major bile duct stenoses. Several potential mechanisms of action of UDCA have been proposed, including intracellular modulation of signaling events and secretion. Various immunosuppressive drugs have been evaluated alone or in combination with UDCA-especially for the treatment of PBC. Of these drugs,the topical corticosteroid budesonide, together with UDCA, appears promising in the treatment of early stage PBC, but data remain insufficient to warrant use of budesonide outside of controlled studies.

Effects of bile acids on biliary epithelial cell proliferation and portal fibroblast activation using rat liver slices

During cholestasis, bile acids accumulate in the liver, and induce cellular alterations. Cholestasis is a major cause of liver fibrosis. We have used precision-cut liver slices (PCLS) in culture to investigate the effects of bile acids on hepatic cells. Rat PCLS were placed on an insert in a vial containing culture medium, and gently agitated on a roller platform. PCLS were treated with 100 microM taurolithocholate (TLC), taurodeoxycholate (TDC) or taurocholate (TC) for 24 or 48 h. PCLS viability was measured, and immunohistochemistry was performed with antibodies against active caspase 3, platelet-derived growth factor (PDGF) receptor-beta and ED-A fibronectin. TDC and TLC, two hydrophobic bile acids, induced hepatocyte necrosis and apoptosis, whereas TC, an hydrophilic bile acid, improved slice viability as compared with controls. Both TDC and TC induced biliary epithelial cell proliferation, together with portal fibroblast proliferation and activation, as shown by PDGF receptor-beta and ED-A fibronectin expression. TLC induced biliary epithelial cell apoptosis. Our results indicate that individual bile acids induce cell type-specific effects in a complex liver microenvironment. The fact that PCLS support biliary epithelial cell and portal fibroblast proliferation will make this model very useful for the study of the mechanisms involved in portal fibrosis.

Prevalence and clinical significance of immunoglobulin A antibodies against tissue transglutaminase in patients with diverse chronic liver diseases

The prevalence of celiac disease (CD) and the prevalence and clinical significance of anti-tissue transglutaminase (tTG) antibodies (tTGAbs) in a large series of patients with chronic liver diseases were assessed. We studied 738 patients (462 with chronic viral hepatitis, 117 with autoimmune liver diseases, 113 with alcoholic or nonalcoholic fatty liver disease, and 46 with other liver disorders) and 1,350 healthy controls (HC). Immunoglobulin A (IgA) tTGAbs were measured by enzyme-linked immunosorbent assay and a microsphere-based flow cytometric assay. Positive sera were investigated for IgA antiendomysial antibodies (EmA). IgA tTGAb-positive subjects were invited to undergo a small-intestinal biopsy and HLA-DQ allele typing. Four of 1,350 HC (0.3%) tested tTGAb(+) EmA(+) and underwent a biopsy (CD confirmation in all). Four of 738 liver disease patients tested tTGAbs(+) EmA(+) (0.54%; not statistically significant). Two were HCV infected (1.24%; not statistically significant), and two had transaminasemia of unknown origin. Forty-three patients tested tTGAbs(+) EmA(-) (5.8%; P<0.001 compared to HC). Inhibition experiments verified the existence of specific IgA anti-tTG reactivity. Twenty-six of 43 patients underwent a biopsy (all negative for CD). Binary logistic regression analysis revealed age (P=0.008), cirrhosis (P=0.004), alkaline phosphatase (P=0.026), and antinuclear antibodies (P=0.012) as independent risk factors for tTGAb reactivity among the patients. It was concluded that CD prevalence is the same in HC and patients with chronic liver diseases. The prevalence of tTGAbs is higher in hepatic patients compared to HC, but their specificity for CD diagnosis in this group of patients is low. tTGAbs in patients appear to be associated with the presence of autoimmunity, cirrhosis, and cholestasis, irrespective of the origin of the liver disease.

Conjugated bile acids promote ERK1/2 and AKT activation via a pertussis toxin-sensitive mechanism in murine and human hepatocytes

Several studies have argued that G-protein-coupled receptors (GPCR) have the capacity to promote activation of receptor tyrosine kinases. The current studies were performed to examine the regulation of the extracellular regulated kinase (ERK)1/2 and AKT pathways by conjugated and unconjugated bile acids in primary hepatocytes. Deoxycholic acid (DCA), chenodeoxycholic acid (CDCA), taurodeoxycholic acid (TDCA), glycodeoxycholic acid (GDCA), taurochenodeoxycholic acid (TCDCA), glycochenodeoxycholic acid (GCDCA), taurocholic acid (TCA), glycocholic acid (GCA), and tauroursodeoxycholic acid (TUDCA) all activated ERK1/2 in primary rat hepatocytes that was abolished by inhibition of ERBB1, and significantly reduced by ROS quenching agents. Bile acid-induced AKT activation was blunted by preventing ERBB1 activation and ROS generation. Treatment of rat hepatocytes with pertussis toxin (PTX) did not alter ERK1/2 and AKT activation induced by DCA or CDCA but abolished pathway activations by conjugated bile acids. Similar data to those with PTX were obtained when a dominant negative form of G(i1alpha) was overexpressed. Treatment of rat hepatocytes with TDCA and TCA promoted guanosine triphosphate (GTP) loading of G(i1alpha), G(i2alpha), and G(i3alpha) in vitro. Treatment of rat hepatocytes with PTX abolished TDCA-induced tyrosine phosphorylation of ERBB1. Similar findings to those in rat hepatocytes were also obtained in primary mouse and human hepatocytes, but not in established rodent or human hepatoma cell lines. In conclusion, collectively our findings demonstrate that unconjugated bile acids activate hepatocyte receptor tyrosine kinases and intracellular signaling pathways in a ROS-dependent manner. In contrast, conjugated bile acids primarily activate receptor tyrosine kinases and intracellular signaling pathways in a GPCR (G(ialpha))-dependent and ROS-dependent manner.

Inhibition of insulin/IGF-1 receptor signaling enhances bile acid toxicity in primary hepatocytes

Modulation of ERBB and insulin-like growth factor 1 (IGF-1) receptor function is recognized as a potential mechanism to inhibit tumor growth. We and others have shown that inhibition of ERBB1 can enhance bile acid toxicity. Herein, we extend our analyses to examine the impact of insulin/IGF-1 receptor inhibition on primary hepatocyte survival when exposed to the secondary bile acid deoxycholic acid (DCA) and compare the impact inhibition of this receptor has on bile acid toxicity effects to that of ERBB1/MEK1/2 inhibition. The insulin/IGF-1 receptor inhibitor NVP-ADW742 at concentrations which inhibit both the insulin and IGF-1 receptors had a modest negative impact on hepatocyte viability, and strongly potentiated DCA-induced apoptotic cell death. Identical data were obtained expressing a dominant negative IGF-1 receptor in hepatocytes; a receptor which acts to inhibit both the IGF-1 receptor and the insulin receptor in trans. Inhibition of ERBB1 function using Iressa (gefitinib) or the tyrphostin AG1478 had more modest effects at enhancing DCA lethality than inhibition of the insulin/IGF-1 receptor function. In contrast, over-expression of a dominant negative ERBB1 protein had pleiotropic effects on multiple signaling pathways in an apparently non-specific manner. These findings suggest that novel therapeutic kinase inhibitors, targeted against growth factor receptors, have the potential to promote bile acid toxicity in hepatocyte when bile flow may be impaired.

Current Understanding of Gender Dimorphism in Hepatic Pathophysiology1

Studies have shown gender dimorphic response of the liver for various hepatic stresses including ischemia/reperfusion, hemorrhagic shock-resuscitation, hepatectomy, liver cirrhosis, endotoxemia, and chronic alcoholic consumption. The mechanisms responsible for the gender dimorphic response include differences in pro-inflammatory cytokine release, production of reactive oxygen species, and alteration in hepatic vasoregulatory action. These effects were shown to be modulated by circulating sex steroid levels. In this regard, modulation of sex steroid levels by agents/drugs has been proposed as a therapeutic option for preventing hepatic damage in various hepatic stress models. Further elucidation of precise mechanisms responsible for the gender-related differences in the hepatic pathophysiology is essential for the potential clinical application of sex hormone modulation therapy. In this article, current progress in our understanding the gender difference in the hepatic pathophysiology under the condition of hepatic stress is reviewed and discussed.

Chemical modifications of bile acids under high-intensity ultrasound or microwave irradiation

High-intensity ultrasound (HIU) and microwave (MW) irradiation, having emerged as effective promoters of organic reactions, were exploited for the synthesis of bile acids derivatives. Esterification, amidation, hydrolysis, oxidation, and reduction were investigated. Compared to conventional methods, both techniques proved much more efficient, increasing product yields and dramatically cutting down reaction times. Scaled-up studies are now under way.

Small-duct primary sclerosing cholangitis. A single-center seven-year experience

Patients with cholestatic liver function tests and histological features of primary sclerosing cholangitis (PSC) but without the typical cholangiographic changes are considered to have small-duct PSC. The incidence of small-duct PSC and the natural history still is not known. We performed a retrospective search for patients diagnosed with small-duct PSC between January 1997 and December 2003. The diagnosis of small-duct PSC was based on biochemical features of chronic cholestasis, liver biopsy findings consistent with PSC, and a normal cholangiogram on endoscopic retrograde cholangiography. Six patients fulfilled the diagnostic criteria for small-duct PSC. All patients received medical therapy. After a mean follow-up time of 26.0 +/- 29.8 months (range, 7-84 months), all patients are alive. Repeated liver biopsy was performed in one patient, 58 months after the initial one, and disclosed amelioration of histological findings (reduction in the Ludwig fibrosis score from 4 to 2). During follow-up symptoms disappeared in all patients who were symptomatic at diagnosis; none of those who were asymptomatic at diagnosis developed symptoms. At the time of last follow-up all patients showed significant improvement of their biochemical variables compared to baseline. Administration of aminosalicylates seemed to be of benefit irrespective of the presence of inflammatory bowel disease. No patients underwent liver transplantation or developed cholangiocarcinoma. Even though our study included a low number of patients and the follow-up time was relatively short, we can suggest that small-duct PSC rarely progresses to large-duct PSC and does not seem to be associated with development of cholangiocarcinoma. It thus seems to represent a separate entity with a favorable prognosis.

Immune response to lipopolysaccharide in primary biliary cirrhosis and autoimmune diseases

A bacteriological aetiology is suspected to be the triggering factor in primary biliary cirrhosis. We studied lipid A, the toxic and immunogenic moiety of gram-negative bacteria lipopolysaccharide, which accumulates abnormally in Kupffer cells, hepatocytes, and biliary epithelial cells in primary biliary cirrhosis patients. Anti-lipid A antibody levels from serum samples from 36 primary biliary cirrhosis patients, drawn before and after ursodeoxycholic acid treatment, were compared to those from patients with other liver diseases (n=236), non-hepatic diseases (n=249), and healthy subjects (n=75). In primary biliary cirrhosis patients, the prevalence of IgM anti-lipid A antibodies was higher before than after ursodeoxycholic acid therapy (64% vs 22%, respectively; P<0.001). Patients with anti-lipid A antibodies had significantly higher IgM levels than those without antibodies (8.7+/-1.1 g/l vs 4.4+/-0.8 g/l, P<0.02). Total IgM levels were correlated with anti-lipid A antibody levels (r=0.65, P<0.02). After therapy, the serum IgM levels decreased significantly (P<0.03). These results indicate that bacterial antigens may participate in the observed increase of serum IgM levels, and support an aetiological role of a gut-derived endotoxin antigen in the pathogenesis of primary biliary cirrhosis.

Bile acids induce mitochondrial ROS, which promote activation of receptor tyrosine kinases and signaling pathways in rat hepatocytes

Previous studies have demonstrated in hepatocytes that deoxycholic acid (DCA) promotes inactivation of protein tyrosine phosphatases (PTPases) and activation of ERBB1 and the extracellular-regulated kinase (ERK) 1/2 pathway. The present studies have determined the biochemical mechanism(s) through which these events occur. DCA and taurodeoxycholic acid (TDCA) (100 micromol/L) caused activation of ERBB1, insulin receptor, and the ERK1/2 and AKT pathways in primary rodent hepatocytes. DCA- and TDCA-induced receptor and signaling pathway activations were blocked by the reactive oxygen species (ROS) scavengers N-acetyl cysteine (NAC) and Trolox (TX), as well as by cyclosporin A (CsA) and bongkrekic acid (BKA). DCA activated the ERK1/2 pathway in HuH7 human hepatoma cells that was blocked by the incubation of cells with an ERBB1 inhibitor, NAC, TX, CsA, or BKA. DCA did not activate the ERK1/2 pathway in mitochondria-defective HuH7 Rho 0 cells. In HuH7 cells and primary hepatocytes, DCA enhanced the production of ROS, an effect that was abolished in Rho 0 cells and by prior incubation of cells with CsA or BKA. In hepatocytes and HuH7 cells, DCA inhibited PTPase activity. Incubation of hepatocytes with either CsA or BKA prevented DCA-induced inhibition of PTPase activity. Loss of mitochondrial function in Rho 0 cells also abolished the inhibitory effects of DCA on PTPase activity. In conclusion, DCA and TDCA cause ROS generation in hepatocytes that is dependent on metabolically active mitochondria. The generation of ROS is essential for PTPase inactivation, receptor tyrosine kinase activation, and enhanced signaling down the ERK1/2 and AKT pathways.

Improved effects of viral gene delivery of human uPA plus biliodigestive anastomosis induce recovery from experimental biliary cirrhosis

Gene therapy may represent a new avenue for the development of multimodal treatment for diverse forms of cirrhosis. This study explores the potential benefits of combining adenovirus-mediated human urokinase-plasminogen activator (AdHuPA) gene delivery and biliodigestive anastomosis to enhance the therapeutic efficacy of each treatment alone for cholestatic disorders resulting in secondary biliary cirrhosis. In an experimental model of secondary biliary cirrhosis, application of 6 x 10(11) vp/kg AdHuPA adenovirus vector resulted in 25.8% liver fibrosis reduction and some improvement in liver histology. The relief of bile cholestasis by a surgical procedure (biliodigestive anastomosis) combined with AdHuPA hepatic gene delivery rendered a synergistic effect, with a substantial 56.9 to 42.9% fibrosis decrease. AdHuPA transduction resulted in clear-cut expression of human uPA protein detected by immunohistochemistry and induction of up-regulation in the expression of metalloproteinases MMP-3, MMP-9, and MMP-2. Importantly, functional hepatic tests, specifically direct bilirubin, were improved. Also, hepatic cell regeneration, rearrangement of hepatic architecture, ascites, and gastric varices improved in cirrhotic rats treated with AdHuPA but not in counterpart AdGFP cirrhotic animals. We believe this might represent a novel therapeutic strategy for human cholestatic diseases.

Mechanism of NO-mediated oxidative and nitrative DNA damage in hamsters infected with Opisthorchis viverrini: a model of inflammation-mediated carcinogenesis

Inflammation mediated by infection is an important factor causing carcinogenesis. Opisthorchis viverrini (OV) infection is a risk factor of cholangiocarcinoma (CHCA), probably through chronic inflammation. Formation of 8-nitroguanine and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), and expression of inducible nitric oxide synthase (iNOS) and heme oxygenase-1 (HO-1) were assessed in the liver of hamsters infected with OV. We newly produced specific anti-8-nitroguanine antibody without cross-reaction. Double immunofluorescence staining revealed that 8-oxodG and 8-nitroguanine were formed mainly in the same inflammatory cells and epithelium of bile ducts from day 7 and showed the strongest immunoreactivity on days 21 and 30, respectively. It is noteworthy that 8-oxodG and 8-nitroguanine still remained in epithelium of bile ducts on day 180, although amount of alanine aminotransferase activity returned to normal level. A time course of 8-nitroguanine was associated with iNOS expression. Furthermore, this study demonstrated that HO-1 expression and subsequent iron accumulation may be involved in enhancement of oxidative DNA damage in epithelium of small bile ducts. In conclusion, nitrative and oxidative DNA damage via iNOS expression in hamsters infected with OV may participate in CHCA carcinogenesis.

Metabolic, antioxidant, nutraceutical, probiotic, and herbal therapies relating to the management of hepatobiliary disorders

Many nutraceuticals, conditionally essential nutrients, and botanical extracts have been proposed as useful in the management of liver disease. The most studied of these are addressed in terms of proposed mechanisms of action, benefits, hazards, and safe dosing recommendations allowed by current information. While this is an area of soft science, it is important to keep an open and tolerant mind, considering that many major treatment discoveries were in fact serendipitous accidents.

Bile acids enhance the activity of the insulin receptor and glycogen synthase in primary rodent hepatocytes

Previously, we demonstrated that deoxycholic acid (DCA)-induced ERK1/2 and AKT signaling in primary hepatocytes is a protective response. In the present study, we examined the regulation of the phosphatidylinositol 3 (PI3) kinase/AKT/glycogen synthase (kinase) 3 (GSK3)/glycogen synthase (GS) pathway by bile acids. In primary hepatocytes, DCA activated ERBB1 (the epidermal growth factor receptor), ERBB2, and the insulin receptor, but not the insulin-like growth factor 1 (IGF-1) receptor. DCA-induced activation of the insulin receptor correlated with enhanced phosphorylation of insulin receptor substrate 1, effects that were both blocked by the insulin receptor inhibitor AG1024 and by expression of the dominant negative IGF-1 receptor (K1003R), which inhibited in trans. Expression of the dominant negative IGF-1 receptor (K1003R) also abolished DCA-induced AKT activation. Bile acid-induced activation of AKT and phosphorylation of GSK3 were blunted by the ERBB1 inhibitor AG1478 and abolished by AG1024. Bile acids caused activation of GS to a similar level induced by insulin (50 nM); both were blocked by inhibition of insulin receptor function and the PI3 kinase/AKT/GSK3 pathway. In conclusion, these findings suggest that bile acids and insulin may cooperate to regulate glucose storage in hepatocytes.

Glucocorticosteroids for primary sclerosing cholangitis

BACKGROUND

Glucocorticosteroids have been suggested for primary sclerosing cholangitis, which is characterised by chronic inflammation and fibrosis in the intrahepatic and extrahepatic biliary tree.

OBJECTIVES

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

SEARCH STRATEGY

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, The Cochrane Central Register of Controlled Trials on The Cochrane Library, MEDLINE, EMBASE from their inception until March 2003, and reference lists.

SELECTION CRITERIA

Randomised clinical trials comparing any dose or duration of glucocorticosteroids versus placebo, no intervention, or other immunosuppressive agents. We included trials irrespective of language, blinding, or publication status.

DATA COLLECTION AND ANALYSIS

Both reviewers extracted data independently and assessed the methodological quality by the generation of the allocation sequence, allocation concealment, double blinding, and follow-up. The results of the meta-analyses were presented as relative risks or weighted mean difference (WMD), both with 95% confidence intervals (CI). The primary outcome measures were mortality and liver-related morbidity.

MAIN RESULTS

Two randomised clinical trials were eligible for inclusion. One trial compared biliary lavage with hydrocortisone versus saline in 17 patients. A significant number of adverse events (pancreatitis; cholangitis with septicaemia; paranoid ideas; fluid retention) and no cholangiographic improvement led to termination of the trial. The other trial compared budesonide versus prednisone in 18 patients. Patients had significantly higher serum bilirubin concentration after treatment with prednisone compared with budesonide (WMD 10.4 micro mol/litre, 95% CI 1.16 to 19.64 micro mol/litre). No other significant effects on clinical or biochemical outcomes were identified for any of the evaluated interventions.

REVIEWERS' CONCLUSIONS

There is no evidence to support or refute peroral glucocorticosteroids for patients with primary sclerosing cholangitis.

Adaptação do modelo experimental de colestase extra-hepática em ratos jovens

Os autores descrevem a adaptação da técnica de ligadura e ressecção do ducto biliar comum descrita na literatura, enfatizando suas vantagens na recuperação pós-cirúrgica. Este trabalho foi realizado no Laboratório Experimental do Departamento de Pediatria da FMB-UNESP.

Polyphenols from Camellia sinenesis attenuate experimental cholestasis-induced liver fibrosis in rats

Accumulation of hydrophobic bile acids during cholestasis leads to generation of oxygen free radicals in the liver. Accordingly, this study investigated whether polyphenols from green tea Camellia sinenesis, which are potent free radical scavengers, decrease hepatic injury caused by experimental cholestasis. Rats were fed a standard chow or a diet containing 0.1% polyphenolic extracts from C. sinenesis starting 3 days before bile duct ligation. After bile duct ligation, serum alanine transaminase increased to 760 U/l after 1 day in rats fed a control diet. Focal necrosis and bile duct proliferation were also observed after 1-2 days, and fibrosis developed 2-3 wk after bile duct ligation. Additionally, procollagen-alpha1(I) mRNA increased 30-fold 3 wk after bile duct ligation, accompanied by increased expression of alpha-smooth muscle actin and transforming growth factor-beta and the accumulation of 4-hydroxynenonal, an end product of lipid peroxidation. Polyphenol feeding blocked or blunted all of these bile duct ligation-dependent changes by 45-73%. Together, the results indicate that cholestasis due to bile duct ligation causes liver injury by mechanisms involving oxidative stress. Polyphenols from C. sinenesis scavenge oxygen radicals and prevent activation of stellate cells, thereby minimizing liver fibrosis.

Tissue Engineering of Human Biliary Epithelial Cells on Polyglycolic Acid/Polycaprolactone Scaffolds Maintains Long-Term Phenotypic Stability

The biliary tree is the target of damage in a number of important liver diseases. Although human biliary epithelial cells (hBECs) can be maintained in vitro for up to 8 weeks, using double-collagen gels, which offer a substantial improvement compared with conventional tissue culture plastic, such gels are unstable and, being only semisolid, they do not lend themselves readily to routine analysis. In this study we have investigated the behavior of primary hBECs on polyglycolic acid (PGA) fiber mesh scaffolds. Experiments showed that PGA fiber mesh scaffolds collapsed after 3 or 4 weeks; hence, in order to improve the integrity of the construct, we also developed a polycaprolactone (PCL)-stabilized PGA scaffold. Cells formed spheroidal aggregates while continuing to proliferate long term and expressing phenotypic stability. Aggregates spontaneously detached from the fibers and could either be left to attach to tissue culture plastic, after which cells spread out and continued to proliferate, or they could be reseeded onto fresh constructs, which then became recolonized and the same pattern of tissue formation was repeated. This behavior was observed even after 6 months and is of major significance because this culture model could therefore be used as a longterm strategy for growing, expanding, and exploiting hBECs for subsequent studies of bile duct morphogenesis and tissue engineering of artificial bile ducts.

Adaptive changes in hepatobiliary transporter expression in primary biliary cirrhosis

BACKGROUND/AIMS

Information about alterations of hepatobiliary transporter expression in primary biliary cirrhosis (PBC) could provide important insights into the pathogenesis of cholestasis. This study aimed to determine the expression of hepatobiliary transport systems for bile salts (Na(+)/taurocholate cotransporter, NTCP; bile salt export pump, BSEP), organic anions (organic anion transporting protein, OATP2; canalicular conjugate export pump, MRP2; basolateral MRP homologue, MRP3), organic cations (canalicular multidrug export pump, MDR1), and phospholipids (canalicular phospholipid flippase MDR3) in livers from patients with advanced stages of PBC.

METHODS

Transporter mRNA and protein levels were assessed by reverse transcription polymerase chain reaction and Western blot analysis. Tissue distribution of transporters was investigated by immunohistochemistry and immunofluorescence microscopy. Hepatic bile acids were measured by gas chromatography-mass spectrometry.

RESULTS

Compared to controls, basolateral uptake systems (NTCP, OATP2) were reduced, canalicular export pumps for bile salts and bilirubin (BSEP, MRP2) were preserved, while canalicular MDR P-glycoproteins (MDR1, MDR3) and the basolateral efflux pump MRP3 were increased in PBC. Double immunofluorescence labeling with a canalicular marker (dipeptidyl peptidase IV) demonstrated proper canalicular localization of BSEP and MRP2 in PBC. OATP2 and MRP2 expression correlated inversely with hepatic levels of hydrophobic bile acids, while positively correlating with hepatic enrichment with ursodeoxycholic acid.

CONCLUSIONS

Down-regulation of basolateral uptake systems and maintenance/up-regulation of canalicular and basolateral efflux pumps may represent adaptive mechanisms limiting the accumulation of toxic biliary constituents.