Dissimilar expression of multidrug resistance mdr1 and bcrp by the replication of hepatitis C virus: role of the nonstructural 5A protein

Multidrug resistance associated with the overexpression of ATP-dependent binding cassette (ABC) proteins is widely accepted as an important cause of treatment failure in patients with neoplastic or infectious diseases. Some of them play also a pivotal role in detoxification processes. Herein, we investigated the effect of hepatitis C virus (HCV) replication and nonstructural 5A (NS5A) protein on the expression and functional activity of two ABC transport proteins: MDR1 and BCRP. RT-quantitative real-time polymerase chain reaction (qPCR) was carried out for mdr1 and bcrp mRNAs in both Huh7 cells expressing NS5A and Huh7.5 cells containing either full-length- or subgenomic-HCV replicon systems. The functional activity of these pumps was studied by performing a dye efflux assay with DiOC2 and Rhodamine 123. A dose-dependent down-regulation of mdr1 expression was documented in Huh7 cells expressing the NS5A protein, as well as in both replicon systems. In contrast, a significant increase of bcrp expression in both systems was recorded, which were in full agreement with the dye efflux assay results. These results warrant further in vivo studies in HCV patients with cholestasis and/or patients that are refractive to the pharmacotherapy due to the activity of these pumps.

Dissimilar expression of multidrug resistance mdr1 and bcrp by the replication of hepatitis C virus: role of the nonstructural 5A protein

Multidrug resistance associated with the overexpression of ATP-dependent binding cassette (ABC) proteins is widely accepted as an important cause of treatment failure in patients with neoplastic or infectious diseases. Some of them play also a pivotal role in detoxification processes. Herein, we investigated the effect of hepatitis C virus (HCV) replication and nonstructural 5A (NS5A) protein on the expression and functional activity of two ABC transport proteins: MDR1 and BCRP. RT-quantitative real-time polymerase chain reaction (qPCR) was carried out for mdr1 and bcrp mRNAs in both Huh7 cells expressing NS5A and Huh7.5 cells containing either full-length- or subgenomic-HCV replicon systems. The functional activity of these pumps was studied by performing a dye efflux assay with DiOC2 and Rhodamine 123. A dose-dependent down-regulation of mdr1 expression was documented in Huh7 cells expressing the NS5A protein, as well as in both replicon systems. In contrast, a significant increase of bcrp expression in both systems was recorded, which were in full agreement with the dye efflux assay results. These results warrant further in vivo studies in HCV patients with cholestasis and/or patients that are refractive to the pharmacotherapy due to the activity of these pumps.

Bilistick: a low-cost point-of-care system to measure total plasma bilirubin

BACKGROUND

Severe neonatal hyperbilirubinemia, with consequent encephalopathy, remains a common cause of morbidity and death in many regions of the world. Poor access to clinical laboratory resources and screening programs to measure plasma bilirubin levels is a major contributor to delayed treatment in developing countries, and the cost of existing point-of-care screening instruments precludes their dissemination.

OBJECTIVES

We are evaluating the accuracy of a low-cost, minimally invasive point-of-care system (Bilistick) requiring a 25-µl blood sample that could be used in low-resource environments to evaluate patients with neonatal jaundice.

METHODS

We compared plasma bilirubin levels in divided blood samples by clinical laboratories and by Bilistick at two medical centers serving term and near-term newborns from ethnically different populations.

RESULTS

118 neonates with bilirubin levels ranging from 24.8 to 501.0 µmol/l were analyzed. The mean bilirubin concentration (±SD) was 215.6 ± 85.5 µmol/l for Bilistick and 226.1 ± 86.4 µmol/l by laboratory determination. Pearson's correlation coefficient between all paired results was 0.961, and the Bland-Altman analysis showed a mean difference of 10.3 µmol/l with a 95% interval of agreement of -38.0 to 58.7 µmol/l.

CONCLUSION

Bilistick is a minimally invasive method for measuring total bilirubin concentration over a wide range of values and should provide an affordable and accurate system for pre-discharge and follow-up screening of jaundiced infants, particularly in low-resource environments.

Relationship between fatty liver and glucose metabolism: a cross-sectional study in 571 obese children

BACKGROUND AND AIMS

Early onset type 2 diabetes mellitus (T2DM) is associated with obesity, insulin resistance and impaired beta-cell function. Non-alcoholic fatty liver disease (NAFLD) may be an independent risk factor for T2DM. We investigated the relationship between NAFLD and glucose metabolism in a large sample of obese children.

METHODS AND RESULTS

A total of 571 obese children (57% males and 43% females) aged 8-18 years were consecutively studied at a tertiary care centre specialised in paediatric obesity. Liver ultrasonography was used to diagnose NAFLD after exclusion of hepatitis B and C and alcohol consumption. Oral-glucose tolerance testing (OGTT) was performed; insulin sensitivity was evaluated by using the insulin sensitivity index (ISI) and beta-cell function by using the ratio between the incremental areas under the curve (AUC) of insulin and glucose (incAUCins/incAUCglu). A total of 41% of the obese children had NAFLD. Impaired glucose tolerance or T2DM was present in 25% of the children with NAFLD versus 8% of those without it (p<0.001). Children with NAFLD had higher body mass index (BMI), fasting glucose, 120-min OGTT glucose, incAUCins/incAUCglu and lower ISI as compared with children without NAFLD (p≤0.002). At bootstrapped multivariable median regression analysis controlling for gender, age, pubertal status and BMI, NAFLD was an independent predictor of 120-min OGTT glucose and ISI, but not of incAUCins/incAUCglu. Similar findings were obtained using continuous liver steatosis as the predictor, instead of dichotomous NAFLD.

CONCLUSION

NAFLD was present in 41% of our obese children and was associated with higher insulin resistance, but not with impaired beta-cell function.

Expression and distribution of aquaporin 8 in rat hepatocytes cold stored 72 hours in modified University of Wisconsin and bes-gluconate-sucrose solutions. Study of their correlation with water content

Since few data are availble on the genetic responses to low temperatures, we investigated if cold storage of hepatocytes (0 degree C, mUW or BGS solutions, 72 h) can affect gene expression and/or cellular localization of AQP8 and their correlation with water movements. Cold preserved hepatocytes showed a significant decrease in water content (P less than 0.05) but were able to regulate their volume when they returned to physiological conditions. These changes were not related to modulation in the expression and the pattern of distribution of AQP8 suggesting that other mechanisms are involved. The study of the quantitative changes in the expression of genes coding for liver specific proteins in cold preserved hepatic cells is of interest in order to develop new preservation methods or solutions that could contribute to maintain the utility of these cells when destined to be applied in clinical models.

HCV, HBV and alcohol - the Dionysos study

Population-based studies on the natural history of chronic viral liver disease that consider co-morbidity factors, such as alcohol or metabolic diseases, are lacking. We report here the contribution of ethanol intake and non-organ-specific autoantibodies (NOSA) to the course of chronic viral disease in the Dionysos cohort. As reported elsewhere, the Dionysos study was performed in two towns of Northern Italy, started in 1992 with 10 years of follow-up in 2002, and allowed us to quantify the burden of chronic liver disease in Northern Italy. We followed 139 subjects with chronic hepatitis C virus (HCV) infection and 61 with chronic hepatitis B virus (HBV) infection for a median (IQR) time of 8.4 (1.0) and 8.3 (0.9) years, respectively. The incidence and remission rates of steatosis were 9.0 and 29.7 per 1,000 person-years in the HCV cohort and 4.0 and 30.4 per 1,000 person-years in the HBV cohort. Progression to cirrhosis and hepatocarcinoma was more common in the HCV than in the HBV cohort. In the HCV cohort, ethanol intake was an independent predictor of liver cirrhosis and of death rate in both cohorts. We found no association between baseline NOSA and 8.4-year mortality. We conclude that morbidity and mortality rate of HBV and HCV infection in the general population is lower than that reported in secondary care populations, blood donors, or clinical series, and that ethanol intake >30 g/day is the most important and evitable risk factor for cirrhosis and death in patients with chronic HCV or HBV infection.

The role of ABC transporters in protecting cells from bilirubin toxicity

The ATP-binding cassette (ABC) superfamily is the largest transporter family known to translocate a wide variety of exogenous and endogenous substrates across cell membranes. In this chapter we review the potential role of three ABC proteins in the transport of unconjugated bilirubin (UCB). These transporters are MRP1, MRP3 and PGP (MDR1). MRP1 is expressed at high levels in most epithelia, usually at the basolateral membrane. Among a multiplicity of substrates, MRP1 mediates the ATP-dependent cellular export of UCB, and its role has been demonstrated in protecting cells from UCB toxicity. MRP3 is an organic anion transporter whose major substrates are GSH conjugates of organic compounds. Among the MRP family members, MRP3 shares the highest degree of amino acid homology with MRP1. Although the hepatic expression of MRP3 has been reported to be up-regulated by bilirubin and bilirubin glucuronides, it is unknown whether MRP3 is also involved in the transport of UCB. PGP is expressed in organs involved in the elimination of endo- and xenobiotics and UCB is one of these substrates. Since the Km of PGP for UCB is well above pathophysiological levels of Bf, it remains uncertain whether it has a role in protecting against UCB cytotoxicity.

A protective effect of breastfeeding on the progression of non-alcoholic fatty liver disease

OBJECTIVE

Non-alcoholic fatty liver disease (NAFLD) is a spectrum of liver disease characterised by accumulation of large-droplet fat in hepatocytes with possible progression to inflammation and fibrosis. Breastfeeding has benefits for child health, both during infancy and later in life, reducing the risk of manifestations of the metabolic syndrome. Here we investigated the association between early type of feeding (breastfed versus formula-fed and duration of breastfeeding) and later NAFLD development.

STUDY DESIGN

We investigated 191 young Caucasian children (3-18 years old) with NAFLD consecutively enrolled between January 2003 and September 2007 in our centre. 48% of these children (n = 91) had been breastfed for a median (interquartile range) time of 8 (7) months.

RESULTS

After correction for age, waist circumference, gestational age and neonatal weight, the odds of non-alcoholic steatohepatitis (NASH) (OR 0.04, 95% CI 0.01 to 0.10) and fibrosis (OR 0.32, 95% CI 0.16 to 0.65) were lower in breastfed versus not breastfed infants. Moreover, the odds of NASH (OR 0.70, exact 95% CI 0.001 to 0.87) and fibrosis (OR 0.86, exact 95% CI 0.75 to 0.98) decreased for every month of breastfeeding.

CONCLUSIONS

This observational study suggests that earlier feeding habits might affect the clinical expression of NASH from 3 to 18 years later, with an apparent drug-like preventive effect of breastfeeding.

Accuracy of body mass index in detecting an elevated alanine aminotransferase level in adolescents

AIM

We evaluated the accuracy of body mass index (BMI) in detecting an elevated alanine aminotransferase (ALT) level in adolescents, taking into account the effects of gender, age, ethanol intake, hepatitis B virus (HBV) and hepatitis C virus (HCV) infections, and drug consumption.

SUBJECTS

A representative sample of 454 adolescents (11-17 years) from two cities in northern Italy was studied (the Dionysos Study).

METHODS

z-BMI was calculated as the z-score of BMI using national growth charts. Logistic regression was used to quantify the contribution of the variables of interest to an elevated ALT (> 30 UL(-1)). Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated, and areas under receiver-operator characteristic curves (AUC) were used to evaluate accuracy.

RESULTS

An elevated ALT was detected in 21 adolescents (4.6%). Among the studied variables, only male gender (OR=6.7, 95% CI 2.0-23.2) and z-BMI (OR=2.1, 95% CI 1.4-3.2) were significant predictors of elevated ALT. The accuracy of the prediction was 0.69 (95% CI 0.59-0.79) for gender and 0.71 (95% CI 0.59-0.81) for z-BMI. By combining gender and z-BMI, the accuracy rose to 0.80 (95% CI 0.71-0.89).

CONCLUSION

BMI is a good predictor of elevated ALT in Italian adolescents and gender adds to the accuracy of the prediction.

Elevated expression and polymorphisms of SOCS3 influence patient response to antiviral therapy in chronic hepatitis C

BACKGROUND

The response to antiviral therapy of chronic hepatitis C virus (HCV) infection is determined by virological, environmental and genetic factors.

OBJECTIVE

The hypothesis was tested that the expression of specific genes and their haplotype frequencies can differentiate between non-responders (NRs) and sustained virological responders (SVRs) to antiviral treatment.

METHODS

A methodological approach based on molecular marker discovery and validation was used to study the genes influencing the antiviral treatment in lymphoblastoid cell lines from 74 genotype 1b HCV patients (44 from Southern Italy and 30 from Northern Italy) treated with pegylated interferon (IFN) alpha and ribavirin. Furthermore, an association study was performed, testing three single nucleotide polymorphisms (SNPs) of suppressor of cytokine signalling 3 (SOCS3) in 162 NR and 184 SVR subjects (SOCS3 -8464 A/C (rs12952093), -4874 A/G (rs4969170) and 1383 A/G, (rs4969168)).

RESULTS

SOCS3 basal expression levels were significantly increased in two independent sets of NR groups (p<0.05). A highly significant association was found between NRs and both the positively associated haplotype (OR = 2.01, 95% CI 1.45 to 2.79, p = 0.0002) and the negatively associated haplotype (OR = 0.56, 95% CI 0.42 to 0.76, p = 0.0014). In particular, the SOCS3 -4874 AA genotype was strongly associated with failure of antiviral therapy (OR = 4.00, 95% CI 2.09 to 7.66, p = 0.0003) and the AA genotype carriers had significantly higher SOCS3 mRNA and protein levels (p<0.05).

CONCLUSIONS

Basal levels of SOCS3, an inhibitor of the IFN alpha-induced Janus kinase-signal transducer and activator of transcription pathways, and its genetic polymorphisms influence the outcome of antiviral treatment. SOCS3 thus represents a novel blood biomarker for the a priori prediction of treatment response.

The expression levels of the translational factors eEF1A 1/2 correlate with cell growth but not apoptosis in hepatocellular carcinoma cell lines with different differentiation grade

Despite the involvement of the elongation factors eEF1A (eEF1A1 and eEF1A2) in the development of different cancers no information is available on their possible contribution to the biology of hepatocellular carcinoma (HCC). We investigated the expression of both forms of eEF1A in HepG2 and JHH6 cell lines considered to be a good in vitro model of HCC at different stage of differentiation. Our data indicate that the mRNA amount of eEF1A1 is increased in both cell lines as compared to normal liver tissue, but eEF1A2 mRNA level is markedly increased only in JHH6. Moreover, the less differentiated cell line JHH6 displays higher EEF1A1 and EEF1A2 mRNAs levels and an higher nuclear-enriched/cytoplasm ratio of EEF1A protein compared to the better differentiated HepG2 cell line. Over-expression depends only partially on gene amplification. The more abundant mRNA levels and the higher nuclear-enriched/cytoplasm ratio of eEF1A in JHH6 neither correlate with apoptosis resistance nor with proliferation rate in sub-confluent cells. However, in confluent cells, a clear tendency to maintain JHH6 into the cell cycle was observed. In conclusion, we document the increased mRNA levels of EEF1A genes in HCC cell lines compared to normal liver. Additionally, we show the increased nuclear-enriched/cytoplasmic protein ratio of eEF1A and the marked raise of the expression of both eEF1A forms in JHH6 compared to HepG2, suggesting the possibility that eEF1A forms might become a relevant markers related to HCC tumor phenotype.

Role of multidrug resistance-associated protein 1 expression in the in vitro susceptibility of rat nerve cell to unconjugated bilirubin

Nerve cell injury by unconjugated bilirubin (UCB) has been implicated in brain damage during neonatal hyperbilirubinemia, particularly in the preterm newborn. Recently, it was shown that UCB is a substrate for the multidrug resistance-associated protein 1 (Mrp1), an ATP-dependent efflux pump, which may decrease UCB intracellular levels. To obtain a further insight into the role of Mrp1 in the increased vulnerability of immature cells to UCB, we evaluated the mRNA and the protein levels of Mrp1 throughout differentiation in primary cultures of rat neurons and astrocytes. Furthermore, in order to provide supportive evidence for the role of Mrp1 in the protection of nerve cells from UCB-induced effects, we evaluated cell susceptibility to UCB when Mrp1 was inhibited with MK571 ((E)-3-[[[3-[2-(7-chloro-2-quinolinyl) ethenyl]phenyl]-[[3-dimethylamino)-3-oxopropyl]thio]methyl]thio]-propanoic acid). The results are the first to demonstrate that Mrp1 is expressed in neurons and that both mRNA and protein levels of Mrp1 increase with cell differentiation. Additionally, inhibition of Mrp1 was associated with an increase in UCB toxic effects, namely cell death, cell dysfunction, and secretion of interleukin (IL)-1beta, tumor necrosis factor (TNF)-alpha, as well as of glutamate. These results point to a novel role of Mrp1 in the susceptibility of premature babies to UCB encephalopathy, and provide a startup point for the development of a new therapeutic strategy.

Predictors of non-alcoholic fatty liver disease in obese children

OBJECTIVE

To evaluate predictors of non-alcoholic fatty liver disease (NAFLD) in obese children.

DESIGN

Cross-sectional study.

SUBJECTS

Two hundred and sixty-eight obese children not consuming alcohol and without hepatitis B or C were consecutively studied at an auxology clinic.

MEASUREMENTS

Alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl-transferase (GGT), cholesterol, high-density lipoprotein (HDL)-cholesterol, low-density lipoprotein (LDL)-cholesterol, triglycerides, uric acid, glucose, glucose during oral glucose tolerance testing (OGTT), insulin, insulin during OGTT, insulin resistance as estimated by homeostasis model assessment (HOMA), C-reactive protein (CRP), and systolic and diastolic blood pressure were measured. Fatty liver was diagnosed by ultrasonography using standard criteria. Univariable and multivariable logistic regression was used to evaluate predictors of NAFLD. All predictors except gender and pubertal status were modeled as continuous variables.

RESULTS

NAFLD was detected in 44% of obese children. At univariable analysis, male gender, Z-score of body mass index (BMI) (Z-BMI), ALT, AST, GGT, triglycerides, uric acid, glucose, glucose during OGTT, insulin, insulin during OGTT, HOMA, CRP and systolic blood pressure were predictors of NAFLD, whereas HDL-cholesterol and late-pubertal status were predictors of the normal liver. At multivariable analysis, however, only Z-BMI, ALT, uric acid, glucose during OGTT and insulin during OGTT were independent predictors of NAFLD.

CONCLUSION

Z-BMI, ALT, uric acid, glucose during OGTT and insulin during OGTT are independent predictors of NAFLD in Italian obese children, with most of the prediction explained by ALT and Z-BMI.

HBV, HCV, and TTV detection by in situ polymerase chain reaction could reveal occult infection in hepatocellular carcinoma: comparison with blood markers

OBJECTIVE

To report a retrospective analysis on the presence of hepatitis B virus (HBV), hepatitis C virus (HCV), and transfusion transmitted virus (TTV) sequences in formalin fixed, paraffin embedded liver biopsies from eight patients with hepatocellular carcinoma, in comparison with blood markers.

METHODS

A direct in situ polymerase chain reaction (PCR) technique was developed for the detection and localisation of genomic signals in the liver tissue. Conventional serological and molecular methods were used for blood evaluation.

RESULTS

In situ PCR showed the presence of one of the three viruses (four HCV, two HBV, and one TTV) in seven of the eight patients. In addition, a co-infection with HBV and HCV was detected in one patient. HCV and HBV sequences were located in the cytoplasm and the nucleus, respectively. When compared with blood markers, these findings were compatible with one occult HBV and two occult HCV infections.

CONCLUSIONS

These findings provide further evidence for occult HBV and HCV infections in cancerous tissues from patients with hepatocellular carcinomas. In situ PCR could be an additional tool for evaluating the viral aetiology of hepatocellular carcinoma alongside conventional diagnostic procedures.

Epidemiology of hepatitis C virus infection

Although a lot of novel information and data on the epidemiology of hepatitis C virus (HCV) infection are available worldwide, the majority of these information are often fragmentary and sometimes contradictory. This review tries to highlight all the data available on the prevalence (i.e. the number of cases present in a known population), the risk factors, the natural history and the incidence (i.e. the number of new cases that occur every year) of HCV infection in the world, and particularly in Italy.

New concepts in bilirubin encephalopathy

Revised concepts of bilirubin encephalopathy have been revealed by studies of bilirubin toxicity in cultured CNS cells and in congenitally jaundiced Gunn rats. Bilirubin neurotoxicity is related to the unbound (free) fraction of unconjugated bilirubin (Bf), of which the dominant species at physiological pH is the protonated diacid, which can passively diffuse across cell membranes. As the binding affinity of plasma albumin for bilirubin decreases strikingly as albumin concentration increases, previously reported Bf values were underestimated. Newer diagnostic tests can detect reversible neurotoxicity before permanent damage occurs from precipitation of bilirubin (kernicterus). Early toxicity can occur at Bf only modestly above aqueous saturation and affects astrocytes and neurons, causing mitochondrial damage, resulting in impaired energy metabolism and apoptosis, plus cell-membrane perturbation, which causes enzyme leakage and hampers transport of neurotransmitters. The concentrations of unbound bilirubin in the cerebro-spinal fluid and CNS cells are probably limited mainly by active export of bilirubin back into plasma, mediated by ABC transporters present in the brain capillary endothelium and choroid plexus epithelium. Intracellular bilirubin levels may be diminished also by oxidation, conjugation and binding to cytosolic proteins. These new concepts may explain the varied susceptibility of neonates to develop encephalopathy at any given plasma bilirubin level and the selective distribution of CNS lesions in bilirubin encephalopathy. They also can suggest better strategies for predicting, preventing and treating this syndrome.

Body mass index is a good predictor of an elevated alanine transaminase level in the general population: hints from the Dionysos study

AIM

To establish the contribution of body mass index (BMI), sex, age, ethanol intake, hepatitis B (HBV) and hepatitis C (HCV) virus infection, coffee and drug consumption, and cigarette smoking to account for an elevated alanine transaminase (ALT) level in the general population.

SUBJECTS

A total of 6315 adult subjects from the Dionysos study.

METHODS

Logistic regression was used to quantify the contribution of the variables of interest to elevated ALT, defined as a value of ALT>60 U/l. Areas under ROC curves (AUCs) were calculated to assess accuracy.

RESULTS

All the variables considered, with the exception of coffee and drug consumption, were significant predictors of elevated ALT at univariable analyses. When significant predictors were employed in a multivariable model, age and cigarette smoking were no longer significant. The AUC was 0.77 (95% CI=0.74-0.80) for the multivariable model and 0.64 (95% CI=0.60-0.68) for the univariable BMI model (p<0.0001 for the comparison).

CONCLUSION

BMI is a good predictor of elevated ALT serum activity in the general population. The ability to predict an elevated ALT is however increased substantially by considering sex, ethanol intake, HBV and HCV infection together with BMI.

Evidence for carrier-mediated transport of unconjugated bilirubin across plasma membrane vesicles from human placental trophoblast

Unconjugated bilirubin (UCB) is currently believed to cross the placenta only by passive diffusion. To assess whether carrier-mediated transport might be involved, the uptake of [(3)H]-UCB by basal (bTPM) and apical (aTPM) plasma membrane vesicles from human placental trophoblast at term was investigated. In both types of vesicles, the uptake of [(3)H]-UCB into an osmotically sensitive space was temperature-dependent, independent of the presence of Na(+), and not affected by changes in membrane potential. The uptake of [(3)H]-UCB by aTPM, but not bTPM, was activated by ATP hydrolysis and inhibited by vanadate. Thus, the exact contribution of both inside out and right-side out bTPM to UCB uptake could not be distinguished, while only inverted aTPM were expected to carry out ATP-dependent UCB uptake. In bTPM and aTPM, uptake of free (unbound) [(3)H]-UCB (B(f)) consisted of a dominant, saturable, presumably carrier-mediated process and a diffusional component that became predominant only at B(f) near or above aqueous solubility limit for UCB (70 nM ). For bTPM, K(m)=7.2 nM; V(max)=9.8 pmol/20s/mg protein; and diffusion coefficient (K(D))=0.14 ml/20s/mg protein. For aTPM in the presence of 9.5m M ATP, K(m)=18 n M; V(max)=131 pmol/20s/mg protein; and K(D)=0.47 ml/20s/mg protein. The uptake of [(3)H]-UCB by bTPM was cis-inhibited by estrone-3-sulfate and estradiol-17 beta-glucuronide and trans-stimulated by unlabelled UCB and bromosulphopthalein. ATP-dependent UCB uptake by aTPM was cis-inhibited by doxorubicin, cholic acid, methotrexate and pronenecid. These findings suggest the presence of distinct transporters in the two domains of human placental trophoblast that could cooperate to transfer UCB from the foetus to the maternal circulation.

In situ polymerase chain reaction detection of transfusion-transmitted virus in liver biopsy

The potential role of transfusion-transmitted virus (TTV) infection in determining liver damage is poorly understood and no information exists about TTV replication within hepatocytes. In this study, we assess TTV in situ PCR in liver tissue. Twenty-one patients with different degrees of liver damage were studied by both serum TTV-DNA detection and in situ TTV PCR analysis and extractive PCR in liver biopsy paraffin sections (FFPE). Extractive PCR and in situ PCR detected TTV-DNA both in serum and liver tissue of five patients. The presence of TTV in serum matched with that found in the liver and TTV sequences were never found independently in liver or serum. Four out of five TTV-DNA-positive patients have not other known cause of liver damage while in one a coinfection from HCV was observed. Our data indicate that in situ PCR appears to be a reliable tool for the detection of TTV-DNA in FFPE, and may help detecting unknown origin of liver damage.

Preparation of an antibody recognizing both human and rodent MRP1

Based on the high level of identity among human, mouse, and rat MRP1 protein sequence, we produced a specific polyclonal antibody (MRP1-A23) against a synthetic polypeptide covering the C-terminus of the human protein. Western blot analysis showed a reactivity against human MRP1 similar to that obtained with the monoclonal QCRL1 antibody. Differently from other available antibodies against human MPR1, MRP1-A23 also detected both rat and mouse MRP1. No cross-reactivity was observed with either human or mouse MRP2 while MRP1-A23 weakly cross-reacted with rat MRP2 in the protein region ranging from 1512 to 1533 amino acids. These data indicate that MRP1-A23 allows specific MRP1 detection in both human and rodent tissues and may provide an important tool in the study of MRP1 expression and function in both experimental and clinical materials.

Pitfalls in preparation of (3)H-unconjugated bilirubin by biosynthetic labeling from precursor (3)H-5-aminolevulinic acid in the dog

We report problems encountered during preparation of tritium-labeled unconjugated bilirubin ((3)H-UCB) from precursor (3)H-5-aminolevulinic acid ((3)H-ALA) in 2 dogs with external biliary drainage installed into the animals under general anesthesia. Under prolonged sedation, 12.9 or 14.0 mCi of (3)H-ALA was administered intravenously in two divided doses, and bile was collected for 9 hours. In one animal, taurocholate (TC) infusion was needed to maintain bile flow. (3)H-UCB was isolated from the bile and recrystallized with the improved method of Webster et al (Webster CC, Tiribelli C, Ostrow JD. J Lab Clin Med 2001;137:370-3). Based on radioactivity and pigment content, hourly bile collections were pooled to optimize specific activities. Surprisingly, in the first dog, only 2.9% of injected radioactivity was recovered in bile and only 14.1% in urine, and the specific activities of the crystalline (3)H-UCB from the two pools were only 39.5 and 30.0 x 10(3) dpm/microg. High-performance liquid chromatography analysis revealed that only 4% of ALA degraded during 5 minutes in injection solution at pH 6.8. The low incorporation of (3)H-ALA and low specific activity of (3)H-UCB was apparently caused mainly by prior degradation and exchange of labile tritium of the (3)H-ALA and probably by enhanced endogenous ALA synthesis caused by the anesthetic/sedative agents. Revised procedures in the second dog improved the incorporation of (3)H-ALA to 11.9% excreted in bile and the specific activity of the crystalline (3)H-UCB to 122.0 and 50.8 x 10(3) dpm/microg, while urinary excretion of tritium increased to 28.5%. These experiences emphasize possible pitfalls in preparing (3)H-UCB by biosynthetic labeling from (3)H-ALA administered to dogs.

Tauroursodeoxycholic acid protects hepatocytes from ethanol-fed rats against tumor necrosis factor-induced cell death by replenishing mitochondrial glutathione

Mitochondrial glutathione (GSH) plays a key role against tumor necrosis factor alpha (TNF)-induced apoptosis because its depletion is known to sensitize hepatocytes to TNF. The present study examined the role of tauroursodeoxycholic acid (TUDCA) administration to chronic ethanol-fed rats on mitochondrial GSH levels and kinetics, mitochondrial membrane physical properties, TNF-induced peroxide formation, and subsequent hepatocyte survival. TUDCA selectively increased the levels of GSH in mitochondria without an effect on cytosolic GSH. This outcome was accompanied by improved initial rate of GSH transport examined at low (1 mmol/L) and high (10 mmol/L) GSH concentrations both in intact mitochondria and mitoplasts prepared from ethanol-fed livers. Assessment of membrane fluidity revealed an increased order parameter in mitochondria and mitoplasts from ethanol-fed rats compared with pair-fed controls, which was prevented by TUDCA administration. Compared with hepatocytes from pair-fed rats, TNF stimulated peroxide generation in hepatocytes from ethanol-fed rats, preceding TNF-induced cell death. Administration of TUDCA to ethanol-fed rats prevented TNF-induced peroxide formation and cell death, an effect that was reversed on depletion of the recovered mitochondrial GSH levels by (R,S)-3-hydroxy-4-pentenoate before TNF treatment. The protective effect of TUDCA against TNF was not because of activation of phosphatidylinositol 3-kinase, discarding a role for a survival-dependent pathway. Thus, these findings reveal a novel role of TUDCA in protecting hepatocytes in long-term ethanol-fed rats through modulation of mitochondrial membrane fluidity and subsequent normalization of mitochondrial GSH levels.

Affinity of human serum albumin for bilirubin varies with albumin concentration and buffer composition: results of a novel ultrafiltration method

Albumin binding is a crucial determinant of bilirubin clearance in health and bilirubin toxicity in certain disease states. However, prior attempts to measure the affinity of albumin for bilirubin have yielded highly variable results, reflecting both differing conditions and the confounding influence of impurities. We therefore have devised a method based on serial ultrafiltration that successively removes impurities in [(14)C]bilirubin until a stable binding affinity is achieved, and then we used it to assess the effect of albumin concentration and buffer composition on binding. The apparent binding affinity of human serum albumin for [(14)C]bilirubin was strongly dependent on assay conditions, falling from (5.09 +/- 0.24) x 10(7) liters/mol at lower albumin concentrations (15 microm) to (0.54 +/- 0.05) x 10(7) liters/mol at higher albumin concentrations (300 microm). To determine whether radioactive impurities were responsible for this change, we estimated impurities in the stock bilirubin using a novel modeling approach and found them to be 0.11-0.13%. Formation of new impurities during the study and their affinity for albumin were also estimated. After correction for impurities, the binding affinity remained heavily dependent on the albumin concentration (range (5.37 +/- 0.26) x 10(7) liters/mol to (0.65 +/- 0.03) x 10(7) liters/mol). Affinities decreased by about half in the presence of chloride (50 mm). Thus, the affinity of human albumin for bilirubin is not constant, but varies with both albumin concentration and buffer composition. Binding may be considerably less avid at physiological albumin concentrations than previously believed.

High prevalence of celiac disease in Italian general population

The worldwide increase of celiac disease prompted us to assess its prevalence in the Italian general population. The 3483 inhabitants of Campogalliano were tested for immunoglobulin A anti-endomysial antibodies. Twenty subjects showed antibody positivity and duodenal biopsy detected typical mucosal lesions of celiac disease in 17 of them; the remaining three cases had a normal villous architecture, but the finding of increased gamma/delta intraepithelial lymphocytes in all and the heterodimer DQA1*0501, DQB1*0201 in two of them was consistent with potential celiac disease. Only one patient had an overt malabsorption syndrome, characterized by diarrhea, weight loss, and severe weakness. In eight subjects atypical symptoms of celiac disease, such as dyspepsia and depression, were present, whereas the remaining subjects were silent. Celiac disease was more frequent in younger age groups. Our cross-sectional design study demonstrates that celiac disease prevalence in the Italian general population is 4.9 per 1000 (95% CI 2.8-7.8), increasing up to 5.7 per 1000 (95% CI 3.5-8.8) with the inclusion of potential cases.

An improved method for isolation of unconjugated bilirubin from rat and dog bile

Radiolabeled unconjugated bilirubin (UCB) is currently prepared by biosynthetic labeling of bilirubin in fistula bile from precursor-labeled delta-aminolevulinic acid (ALA) in rats or dogs. With existing methods, yields of labeled UCB from the bile are generally less than 50%. We here report modifications of the original method of Ostrow et al (Ostrow JD, Hammaker L, Schmid R. The preparation of crystalline bilirubin-C(14). J Clin Invest 1961;40:1442-52) that result in improvement of yields to 72% from both dog and rat bile. The modifications include the initial deproteination of bile with a reverse-phase C18 cartridge, removal of ethanol before alkaline hydro-lysis to avoid esterification of UCB, and adjustments for the high proportion of non-glucuronide UCB conjugates in dog bile not precipitated as lead salts. These improvements should save significantly on both costs and animal usage.

Human leucocyte interferon-alpha in the treatment of chronic hepatitis C

AIM

To assess the efficacy of different schedules of human leucocyte interferon alpha in chronic hepatitis C.

PATIENTS AND METHODS

A total of 213 naive patients with chronic hepatitis C were treated with 4 different schedules of human leucocyte interferon alpha. Sustained response was defined as persistently normal alanine amino transferase values with negative serum hepatitis C virus-RNA up to 12 months after therapy withdrawal.

RESULTS

Rates of sustained response were 16% with 3 MU tiw for 6 months, 33% with 6 MU tiw for 5 months after a priming dose of 9 MU tiw for a month, 32% with 3 MU tiw for 12 months and 20% with 3 MU daily for 6 months. The major factors affecting the response rate were age and the hepatitis C virus genotype, as a sustained response was significantly higher in patients under 45 years and infected by hepatitis C virus types other than hepatitis C virus-1. Treatment was well tolerated and side-effects and drop-out events were similar to those described with other types of alpha-interferons.

CONCLUSIONS

Human leucocyte interferon alpha appears to be equivalent to recombinant interferon-alpha in the treatment of chronic hepatitis C.

Mechanisms for the transport of unconjugated bilirubin in human trophoblastic BeWo cells

To evaluate mechanisms that mediate passage of unconjugated bilirubin (UCB) across placenta, the transport of [3H]UCB was studied in the human trophoblastic, BeWo cell line. When plotted against the unbound UCB concentration [Bf], uptake exhibited saturative kinetics with a similar apparent Km ( approximately 30 nM) for BeWo cells grown either in polarized (Transwell) or non-polarized fashion (dish). UCB release from cells, but not uptake, was inhibited by sulfobromophthalein but not by taurocholate, and almost abolished by MK571, a specific inhibitor of the activity of multidrug resistance-associated proteins (MRPs). MRP1 and MRP5 were both present in BeWo cells and the expression of MRP1, but not MRP5, was markedly higher in polarized cells. These data indicate that UCB is taken up from the fetal circulation by a still undefined, saturative process not shared by other organic anions and is then excreted to maternal circulation by proteins of the MRP family.

DNA oxidative damage in leukocytes correlates with the severity of HCV-related liver disease: validation in an open population study

BACKGROUND/AIMS

Oxidative DNA damage, identifiable in the formation of 8-hydroxydeoxyguanosine (8-OHdG), is relevant in the mutagenesis/carcinogenesis process. The aim of this study was to assess 8-OHdG levels in patients with hepatitis C virus (HCV) infection in relation to extent of liver damage and HCV genotype.

METHODS

8-OHdG levels were measured in DNA from circulating leukocytes of 110 anti-HCV positive subjects belonging to the population of the Dionysos study, subgrouped in: 50 anti-HCV+ with persistently normal ALT, 48 with chronic hepatitis and 12 with cirrhosis. Twenty normal subjects served as Controls. 8-OHdG levels were assayed by HPLC/electrochemical detector.

RESULTS

8-OHdG levels rose (P < 0.00001) from Controls to HCV+; chronic hepatitis and cirrhosis were associated with a further increase (P < 0.02 versus HCV+). Genotype 1 was associated with higher levels of 8-OHdG (P < 0.04). Multiple logistic regression analysis showed that, after correction for potential confoundings, 8-OHdG levels correlated (P < 0.02) with presence and extent of liver damage.

CONCLUSIONS

An accumulation of 8-OHdG in circulating leukocytes is a reliable marker of the extent of liver damage in HCV+ patients and is present in particular in genotype 1 infection. This genomic damage may contribute to liver carcinogenesis by causing persistent DNA changes.

Genetic determinants of ethanol-induced liver damage

BACKGROUND

Although a clear correlation exists between cumulative alcohol intake and liver disease, only some of the alcohol abusers develop signs of ethanol-induced liver damage. To identify some of the genetic variations predisposing persons to alcoholic liver disease (ALD), a genetic study was performed in heavy drinkers from the cohort of the Dionysis study, a survey aimed at evaluating liver disease in the open population of two towns in Northern Italy (6917 individuals).

MATERIALS AND METHODS

158 heavy drinkers (approximately 85% of all heavy drinkers in the population; daily alcohol intake > 120 g in males and >60 g in females) were investigated by the analysis of nine polymorphic regions, mapping in exons III and IX of the alcohol-dehydrogenase (ADH)-2 gene, in exon VIII of the ADH3 gene, in intron VI, in the promoter region of the cytochrome P4502E1 (CYP2E1) gene, and in the promoter region of the tumor necrosis factor-alpha gene.

RESULTS

Heavy drinkers with or without ALD significantly differed for the distribution of alleles of the cytochrome P4502E1 (CYP2E1) and alcohol-dehydrogenase-3 (ADH-3) genes. In one town, allele C2 in the promoter region of the CYP2E1 gene had a frequency of 0.06 in healthy heavy drinkers, of 0.19 in heavy drinkers with ALD (p = 0.012), and of 0.33 in heavy drinkers with cirrhosis (p = 0.033). In the other town, whose inhabitants have different genetic derivation, a prominent association between ALD and homozygosity for allele ADH3*2 of ADH3 was found, with a prevalence of 0.31 in heavy drinkers with ALD and of 0.07 in healthy heavy drinkers controls (p = 0.004). CONCLUSIONS. Both heterozygosity for allele C2 of CYP2E1 and homozygosity for allele ADH3*2 of ADH3 are independent risk factors for ALD in alcohol abusers. The relative contribution of these genotypes to ALD is dependent on their frequency in the population. Overall, heavy drinkers lacking either of these two genotypes are 3.2 and 4.3 times more protected from developing ALD and cirrhosis respectively.

Abc protein transport of MRI contrast agents in canalicular rat liver plasma vesicles and yeast vacuoles

The mechanism of excretion into bile of hepatospecific magnetic resonance imaging (MRI) contrast media employed labeled Gd-reagents EOB.DTPA, BOPTA, B 20790 (iopanoate-linked), and B 21690 (glycocholate-linked) for measurement in rat liver canalicular plasma membrane vesicles and yeast vacuoles. The presence of ATP gave threefold greater transport of B 20790 and B 21690 than of EOB.DTPA and BOPTA. In yeast vacuoles the ATP stimulatory effect was eightfold with B 20790 and fivefold greater for B 21690, whereas in YCF1- or YLLO115w-deleted yeast cells the transport was significantly reduced and absent from double mutants, YCF1 and YLLO15w. The transport was similar in wild-type and deletant cells for B 21690; taurocholate gave 85% inhibition. These data suggest that bilary secretion of structurally related MRI agents depend on molecular structure. The findings are suggestive as of possible value for clinical diagnosis of inherited hyperbilirubinemias and other liver disorders.

Hepatic uptake of organic anions affects the plasma bilirubin level in subjects with Gilbert's syndrome mutations in UGT1A1

Although in Gilbert's syndrome (GS), bilirubin glucuronidation is impaired due to an extra TA in the TATA box of the promoter of the gene for bilirubin UDP-glucuronosyltransferase 1 (UGT1A1), many GS homozygotes lack unconjugated hyperbilirubinemia. Accordingly, an additional defect in bilirubin transport might be required for phenotypic expression. Plasma bilirubin and the early fractional hepatic uptake rate (BSP K(1)) of a low dose of tetrabromosulfophthalein (0.59 micromol/kg) were determined in (1) 15 unrelated patients with unconjugated hyperbilirubinemia plus 12 random controls; (2) 4 unrelated GS probands and 15 of their first-degree relatives; (3) 7 unrelated patients with hemolysis due to beta-Thalassemia minor. Subjects were classified by DNA sequencing of the promoter region of both UGT1A1 alleles. In group 1, GS homozygotes showed a highly significant negative linear correlation between plasma bilirubin levels and BSP K(1). BSP K(1) values overlapped considerably between GS and normal subjects, whereas, in group 2, they were clustered within, and sharply segregated among, families. Patients with hemolysis, despite elevated plasma bilirubin levels, had mean BSP K(1) values similar to the normal subjects. Within each GS subgroup with defined UGT1A1 mutations, the plasma bilirubin level is in part determined by the organic anion uptake rate, assessed by early plasma disappearance of low-dose BSP. The lower BSP uptake in GS is not secondary to the hyperbilirubinemia, but probably caused by (an) independent, genetically determined defect(s) in hepatic transport mechanism(s), shared by BSP and bilirubin, that are likely necessary for phenotypic expression of GS.

Occult hepatitis B virus infection

Many studies have shown that hepatitis B virus infection may also occur in hepatitis B surface antigen-negative patients. This occult infection has been identified both in patients with cryptogenic liver disease and in patients with hepatitis C virus-related chronic hepatitis, and much evidence suggests that it may be a risk factor of hepatocellular carcinoma development. However several aspects of this occult infection remain unclear such as its prevalence and the factor(s) involved in the lack of circulating hepatitis B surface antigen. Moreover, it is uncertain whether the occult hepatitis B virus infection may contribute to chronic liver damage, considering that it is usually associated with a suppressed viral replication. Evidence and hypotheses concerning this fascinating field of bio-medical research are reviewed.

Epidemiology of hepatitis C virus infection in Italy: the slowly unraveling mystery

In spite of the large diffusion of hepatitis C virus (HCV) infection and its high association with liver disease, the epidemiology of HCV in Italy is still unclear. This review collects all the data available on the prevalence and incidence of HCV infection in Italy and compares them with those reported in other countries.

Detection of MRP1 mRNA in human tumors and tumor cell lines by in situ RT-PCR

The detection of the multridrug resistance-associated proteins is becoming increasingly important in assessing tumor sensitivity to treatment. In this work we describe a new, rapid, sensitive, and robust method for the detection of MRP1 expression based on direct RT-in situ-PCR technology and fluorochrome-modified (dCTP(Cy3)) nucleotides. MRP1 expression was found in both placenta (BeWo) and liver (Hep G2)-derived tumor cell line as well as in small cell lung carcinoma. In liver-derived cells, MRP1 expression was detected by RT-in situ-PCR but not by in situ hybridization, suggesting a higher sensitivity of in situ amplification for the low level of expression in Hep G2 cells. RT solution PCR confirmed the presence of MRP1 in BeWo and Hep G2 cells, although the level of the gene expression was lower in liver cells. This method represents a viable alternative to conventional immunohistochemistry, and may be useful in the evaluation of MRP1 expression in different tissue or cell lines.

Risk factors for alcoholic liver disease

Abstract Alcoholic liver disease (ALD) is still a frequent disorder, even though its incidence appears to be decreasing. In spite of intense investigation, the precise mechanisms leading to ALD are still imprecisely known. This is due in part to the lack of a reliable animal model; in part to the difficulty of obtaining clinical data of adequate sample size and derived from unblased populations and finally from the lack of uniformity of the criteria used to define ALD. This paper will review what is known of the various pieces of this puzzle, with particular emphasis not only on the total amount of alcohol consumed, but also on drinking patterns and type of alcoholic beverage ingested. The other potential factors such as age, gender, genetic background, nutritional status, occupational hazards and viral diseases (especially HCV infection) will be touched upon.

Cohort effect of HCV infection in liver cirrhosis assessed by a 25 year study

BACKGROUND

The role of HCV infection in the development of chronic liver disease is still unclear.

OBJECTIVES

Assess the presence of HCV infection in patients with liver cirrhosis.

STUDY DESIGN

123 cases of cirrhotic liver randomly selected over a 25 years period (1969-1994) from the autopsy archives of the Pathology Department of the University of Trieste, Italy, were analyzed for the presence of HCV viral genome.

METHODS

Total RNA was extracted from formalin-fixed paraffin-embedded tissues of the cirrhotic liver. Genotype analysis for HCV was performed after RT-PCR by dot-blot hybridization with the three major genotype-specific probes (G1, G2 and G3).

RESULTS

The overall HCV genome frequency was 50.4% (62/123). The positivity was quite constant in the 1969-1979 period (35-38%), rose to 65% in 1984, peaked to 77% in 1989 (P<0.005 vs. the previous decade), and decreased to 50% in 1994. HCV genotype G1 was found in 89% of the 62 positive samples. The mean age of death of HCV-positive and HCV-negative patients was comparable (69+/-12 vs. 67+/-16 years, NS).

CONCLUSIONS

These data show an increasing frequency of HCV infection in cirrhotic liver tissues from 1969 to 1994, which peaked in 1989. The genotype G1 was the almost uniquely associated with cirrhosis. These findings indicate that the HCV infection occurred around the late 1950s-early 1960s, thus supporting the hypothesis of a cohort effect. HCV infection seems not to alter the natural history of liver cirrhosis as indicated by the comparable age at death of HCV positive and HCV negative patients.

The products of YCF1 and YLL015w (BPT1) cooperate for the ATP-dependent vacuolar transport of unconjugated bilirubin in Saccharomyces cerevisiae

Since bilirubin-like pigments are present in the environment as degradation products of heme-containing proteins, yeast could have developed a detoxifying system to transport these compounds into their vacuoles. Vacuoles from Saccharomyces cerevisiae showed an ATP-dependent, saturative transport of unconjugated bilirubin (UCB) that was reduced by 60% and 40% in YCF1 and YLL015w-deleted cells, respectively; the double deletant showed no UCB uptake. Conversely, the transport of bile acids (taurocholate) was comparable in wild and deleted stains. These data identify YCF1 and YLL015w, named BPT1 (Bile Pigment Transporter), as the genes responsible for ATP-dependent UCB transport in yeast. Since YCF1 and YLL015w are rather homologous with multidrug resistant proteins (MRPs), they also suggest the involvement of this class of transporters in the ATP-dependent transport of unconjugated bilirubin.

The products of YCF1 and YLL015w (BPT1) cooperate for the ATP-dependent vacuolar transport of unconjugated bilirubin in Saccharomyces cerevisiae

Since bilirubin-like pigments are present in the environment as degradation products of heme-containing proteins, yeast could have developed a detoxifying system to transport these compounds into their vacuoles. Vacuoles from Saccharomyces cerevisiae showed an ATP-dependent, saturative transport of unconjugated bilirubin (UCB) that was reduced by 60% and 40% in YCF1 and YLL015w-deleted cells, respectively; the double deletant showed no UCB uptake. Conversely, the transport of bile acids (taurocholate) was comparable in wild and deleted stains. These data identify YCF1 and YLL015w, named BPT1 (Bile Pigment Transporter), as the genes responsible for ATP-dependent UCB transport in yeast. Since YCF1 and YLL015w are rather homologous with multidrug resistant proteins (MRPs), they also suggest the involvement of this class of transporters in the ATP-dependent transport of unconjugated bilirubin.