Comparison of Pig, Human and Rat Hepatocytes as a Source of Liver Specific Metabolic Functions in Culture Systems - Implications for Use in Bioartificial Liver Devices

The limited availability of human hepatocytes results in the use of animal cells in most bioartificial liver support devices. In the present work, clinically relevant liver specific metabolic activities were compared in rat, pig and human hepatocytes cultured on liver-derived biomatrix to optimize the expression of differentiated functions. Pig hepatocytes showed higher rates of diazepam metabolism (2.549±0.821 μg/h/million cells vs. 0.474±0.079 μg/h/million cells rats, p<0.005, and vs. 0.704±0.171 μg/h/million cells in man, p<0.005) and of bilirubin conjugation (21.60116±8.433237 μmoles/l/24 h vs. 6.786809±2.983758 in man, p<0.001 and vs. 9.956538±1.781016 μmoles/l/24 h in rats, p<0.005). Urea synthesis was similar in pig and in human hepatocytes (150±46.3 vs. 144.8±21.46 nmoles/h/million cells) and it was lower in rats (84.38±35.2; p<0.001 vs. man, p<0.02 vs. pig). High liver specific metabolic activities in cultured pig hepatocytes further support their use as a substitue for human cells in bioartificial liver devices

Use of the Needs Evaluation Questionnaire with cancer outpatients

PURPOSE

The Needs Evaluation Questionnaire (NEQ) is a self-administered instrument with 23 dichotomous items that is used both in oncology clinical practice and in research. It was originally developed for use in setting of hospitalization. The aim of the present study was to assess the factor structure of the NEQ in an outpatient oncology sample and to compare the unmet needs of inpatients and outpatients in the Italian context.

METHODS

In 6 Italian oncology departments, 783 patients completed the NEQ. Patients included in the study had different primary tumor sites and were in different phases of the disease and care process. There were 195 inpatients and 588 outpatients total.

RESULTS

Confirmatory factor analysis (CFA) showed that, with outpatients, the NEQ retained the distribution of the items in five main areas previously described with inpatients. Cancer outpatients expressed high percentages of unmet needs primarily concerning "material needs" and "needs for psycho-emotional support." Our survey also suggested that, in addition to the 23 original items, four new items could be tested for specific use with outpatients.

CONCLUSIONS

Our findings highlight the importance of establishing routine assessment of unmet needs also in clinical oncology settings different from wards-such as day hospitals, ambulatory rehabilitation, or follow-up ambulatory care-where, at least in the Italian context, the rate of unmet needs is currently considerably high. The NEQ could be an effective tool for this assessment.

An experimental therapy to improve skeletal growth and prevent bone loss in a mouse model overexpressing IL-6

Premature osteoporosis and stunted growth are common complications of childhood chronic inflammatory disease. Presently, no treatment regimens are available for these defects in juvenile diseases. We identified the sequential Fc-OPG/hPTH treatment as an experimental therapy that improves the skeletal growth and prevents the bone loss in a mouse model overexpressing IL-6.

INTRODUCTION

Premature osteoporosis and stunted growth are common complications of childhood chronic inflammatory diseases and have a significant impact on patients' quality of life. Presently, no treatment regimens are available for these defects in juvenile diseases. To test a new therapeutic approach, we used growing mice overexpressing the pro-inflammatory cytokine IL-6 (TG), which show a generalized bone loss and stunted growth.

METHODS

Since TG mice present increased bone resorption and impaired bone formation, we tested a combined therapy with the antiresorptive modified osteoprotegerin, Fc-OPG, and the anabolic PTH. We injected TG mice with Fc-OPG once at the 4th day of life and with hPTH(1-34) everyday from the 16th to the 30th day of age.

RESULTS

A complete prevention of growth and bone defects was observed in treated mice due to normalization of osteoclast and osteoblast parameters. Re-establishment of normal bone turnover was confirmed by RT-PCR analysis and by in vitro experiments that revealed the full rescue of osteoclast and osteoblast functions. The phenotypic recovery of TG mice was due to the sequential treatment, because TG mice treated with Fc-OPG or hPTH alone showed an increase of body weight, tibia length, and bone volume to intermediate levels between those observed in vehicle-treated WT and TG mice.

CONCLUSIONS

Our results identified the sequential Fc-OPG/hPTH treatment as an experimental therapy that improves the skeletal growth and prevents the bone loss in IL-6 overexpressing mice, thus providing the proof of principle for a therapeutic approach to correct these defects in juvenile inflammatory diseases.

Microbial tracking of multidrug-resistant Klebsiella pneumoniae isolates in a pediatric hospital setting

We investigated the clonal relatedness of seven multi-drug-resistant (MDR) Klebsiella pneumoniae isolates, as well as three susceptible K. pneumoniae isolates collected during hospital outbreaks and outbreak-related microbiological surveillance, respectively. The relatedness among K. pneumoniae isolates was assessed by pulsed field gel electrophoresis (PFGE) and automated repetitive-sequence-based PCR (rep-PCR) genotyping and the results were compared to a proteomic phenotyping performed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). All typing methods agreed on the generation of three different clusters of K. pneumoniae isogenetic/related MDR strains. After strengthening hospital infection control measures, no other spreading events involving MDR-K. pneumoniae were reported until the end of the observation period. This preliminary investigation suggests that, in a hierarchical approach to bacterial typing, MALDI-TOF MS proteome profiling might offer a fast and valuable preliminary screening tool able to support microbiologists during nosocomial outbreak surveys.

Proteomics boosts translational and clinical microbiology

The application of proteomics to translational and clinical microbiology is one of the most advanced frontiers in the management and control of infectious diseases and in the understanding of complex microbial systems within human fluids and districts. This new approach aims at providing, by dedicated bioinformatic pipelines, a thorough description of pathogen proteomes and their interactions within the context of human host ecosystems, revolutionizing the vision of infectious diseases in biomedicine and approaching new viewpoints in both diagnostic and clinical management of the patient. Indeed, in the last few years, many laboratories have matured a series of advanced proteomic applications, aiming at providing individual proteome charts of pathogens, with respect to their morph and/or cell life stages, antimicrobial or antimycotic resistance profiling, epidemiological dispersion. Herein, we aim at reviewing the current state-of-the-art on proteomic protocols designed and set-up for translational and diagnostic microbiological purposes, from axenic pathogens' characterization to microbiota ecosystems' full description. The final goal is to describe applications of the most common MALDI-TOF MS platforms to advanced diagnostic issues related to emerging infections, increasing of fastidious bacteria, and generation of patient-tailored phylotypes. This article is part of a Special Issue entitled: Trends in Microbial Proteomics.

Serum insulin-like growth factor-I (IGF-I) reference ranges for chemiluminescence assay in childhood and adolescence. Data from a population of in- and out-patients

BACKGROUND

Insulin-like growth factor I (IGF-I) measurement is widely used for the diagnosis of disorders of GH secretion and sensitivity, and for monitoring of both GH and IGF-I replacement therapies. However, the lack of appropriate reference values obtained from large and representative samples undermines its practical utility.

OBJECTIVE

To establish IGF-I reference values for a commonly used enzyme-labeled chemiluminescent immunometric assay in a large population of children aged 0 to 18 years.

DESIGN

Cross-sectional analysis of serum IGF-I levels from samples collected in the two major Italian Children's Hospitals.

SUBJECTS AND METHODS

IGF-I was measured using a solid-phase, enzyme-labeled chemiluminescent immunometric assay in 24403 children (50.6% girls) aged 0 to 18 years. Quantile regression coupled to multivariable fractional polynomials was used to produce age- and sex-specific reference values.

MAIN OUTCOME MEASURE

Age- and sex-specific IGF-I reference values.

RESULTS AND CONCLUSION

Reference values for immunometric assay of IGF-I were produced in a large sample of children and adolescents. Prediction equations were provided to automatize their calculations.

Stem and progenitor cells for liver repopulation: can we standardise the process from bench to bedside?

There has been recent progress in the isolation and characterisation of stem/progenitor cells that may differentiate towards the hepatic lineage. This has raised expectations that therapy of genetic or acquired liver disease might be possible by transplanting stem/progenitor cells or their liver-committed progeny. However, it is currently impossible to determine from the many documented studies which of the stem/progenitor cell populations are the best for therapy of a given disease. This is largely because of the great variability in methods used to characterise cells and their differentiation ability, variability in transplantation models and inconsistent methods to determine the effect of cell grafting in vivo. This manuscript represents a first proposal, created by a group of investigators ranging from basic biologists to clinical hepatologists. It aims to define standardised methods to assess stem/progenitor cells or their hepatic lineage-committed progeny that could be used for cell therapy in liver disease. Furthermore standardisation is suggested both for preclinical animal models to evaluate the ability of such cells to repopulate the liver functionally, and for the ongoing clinical trials using mature hepatocytes. Only when these measures have been put in place will the promise of stem/progenitor-derived hepatocyte-based therapies become reality.

Clinical role of calprotectin assay in determining histological relapses in children affected by inflammatory bowel diseases

BACKGROUND

Inflammatory bowel diseases (IBD) are characterized by periods of remission with recurrent episodes of symptom exacerbation because of acute intestinal inflammation, which is correctly evaluated by endoscopy with biopsy sampling. However, many surrogate markers of intestinal inflammation, including fecal calprotectin (FC), are detected as potential predictors of mucosal inflammation in IBD patients. The aim of our study was to retrospectively assess the clinical efficacy of the calprotectin assay in determining histological relapses of pediatric IBD patients.

METHODS

We retrospectively reviewed the histological examinations, clinical records, and FC values of patients who had undergone colonoscopy at our hospital over an 8-year period, from December 31, 1998, to December 31, 2006. Only patients with a first histological examination showing a quiescent IBD who submitted to a second histological examination during the next 3 years were selected.

RESULTS

Seventy-three IBD patients, all with a first biopsy showing a quiescent IBD, were studied; at the second histological examination, 32 presented with relapse and 41 presented with remission. Relapsed patients showed significantly increased FC levels compared with nonrelapsed patients. A FC value of 275 mug/g achieved sensitivity and negative predictive value of 97% and specificity and positive predictive value of 85% in predicting histological relapse.

CONCLUSIONS

FC seems to be a direct measure of intestinal inflammation and therefore a good marker of the risk of histological relapse in pediatric IBD patients. The application of this test in clinical practice may enable the avoidance of invasive tests as well as targeting treatment.

Liver repopulation with bone marrow derived cells improves the metabolic disorder in the Gunn rat

BACKGROUND

Reversible ischaemia/reperfusion (I/R) liver injury has been used to induce engraftment and hepatic parenchymal differentiation of exogenous beta2-microglubulin(-)/Thy1(+) bone marrow derived cells.

AIM

To test the ability of this method of hepatic parenchymal repopulation, theoretically applicable to clinical practice, to correct the metabolic disorder in a rat model of congenital hyperbilirubinaemia.

METHODS AND RESULTS

Analysis by confocal laser microscopy of fluorescence labelled cells and by immunohistochemistry for beta2-microglubulin, 72 hours after intraportal delivery, showed engraftment of infused cells in liver parenchyma of rats with I/R, but not in control animals with non-injured liver. Transplantation of bone marrow derived cells obtained from GFP-transgenic rats into Lewis rats resulted in the presence of up to 20% of GFP positive hepatocytes in I/R liver lobes after one month. The repopulation rate was proportional to the number of transplanted cells. Infusion of GFP negative bone marrow derived cells into GFP positive transgenic rats resulted in the appearance of GFP negative hepatocytes, suggesting that the main mechanism underlying parenchymal repopulation was differentiation rather than cell fusion. Transplantation of wild type bone marrow derived cells into hyperbilirubinaemic Gunn rats with deficient bilirubin conjugation after I/R damage resulted in 30% decrease in serum bilirubin, the appearance of bilirubin conjugates in bile, and the expression of normal UDP-glucuronyltransferase enzyme evaluated by polymerase chain reaction.

CONCLUSIONS

I/R injury induced hepatic parenchymal engraftment and differentiation into hepatocyte-like cells of bone marrow derived cells. Transplantation of bone marrow derived cells from non-affected animals resulted in the partial correction of hyperbilirubinaemia in the Gunn rat.

Regenerative medicine: an insight

Regenerative Medicine is a rapidly evolving field of therapy integrating different scientific and technological areas, including cell biology, biomedical and computer engineering, and clinical medicine, thus creating an interdisciplinary exchange network of skill, ideas, materials and efforts between basic and clinical research. Even if significant achievements have been obtained particularly in Plastic Surgery, Ophthalmology and Orthopedics, the field is still experimental and so far has failed to meet the expectations. The present article reviews the major hurdles that are still hampering the translational "bench to bedside" process and limiting the availability of these innovative therapeutic tools.

The hormone replacement therapy opposed to low dose tamoxifen (HOT) study: safety data from an ongoing phase III trial

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Background: Primary prevention trials have shown that tamoxifen (T) lowers ER+ breast cancer (BC) incidence by 48%. While the IBIS I update showed mixed findings, the Italian trial showed an interesting positive risk/benefit ratio in T and hormone replacement therapy (HRT) users: fewer BC, endometrial cancer comparable to placebo, and no cardiovascular diseases (CVD) excess. In a phase II study, low dose T and HRT showed a safe gynecological profile and did not increase menopausal symptoms. Moreover low dose T maintains the same antiproliferative effects as the standard dose. To improve BC prevention and quality of life (QoL) in menopausal women we started a multicentric, phase III trial of low dose T in HRT users. Methods: current or de novo HRT users are randomized to T 5 mg/day or placebo for 5 yrs. The primary aim is the reduction of invasive or in situ BC. Secondary aims are: safety, gene polymorphisms (SNPs) correlated to BC risk and T activity. In a subgroup transvaginal ultrasound (TvUS) and endometrial biopsy is being performed after 3 years of treatment to monitor endometrial effects. Results: as of December 31 2006, 1870 women were enrolled, of which 21% were hysterectomized. Median age is 53 years (33–72), BMI is <25 in 66%, =25<30 in 26%, >30 in 8%. Current or de novo users are 80% and 20%. 84% participants have at least one follow-up visit. 128 subjects performed already the 3 years TvUS and endometrial biopsy: so far no atypical hyperplasia or cancer was found. A modest increase of menopausal symptoms was observed (hot flashes 42% vs 52%, night sweating 39% vs 44%). Drop-outs are 23%, of which 13% due to AE including: 21 cancers (12 invasive BC, 1 DCIS), 13 CVD (3 VTE), 9 gynecological (5 endometrial polyps). Conclusions: combination of low dose T and HRT has reasonable safety profile, we have reached almost 1,900 women on study and AE rate is very low. These unblinded findings support the safety of the association of HRT and T.

No significant financial relationships to disclose.

Liver and liver cell transplantation for glycogen storage disease type IA

Glycogen storage disease type Ia (GSDIa) is an inherited disorder of glucose metabolism, due to the selective deficiency of the hepatic enzyme glucose-6-phosphatase. Clinical manifestations include severe hypoglycaemia three to four hours post-prandially, increased production of lactic acid, triglycerides and uric acid, hepatic glycogen storage disease with development of multiple adenomas and kidney disease with proteinuria. Liver transplantation is frequently performed in order to achieve metabolic control and when malignant transformation of adenomas is suspected. Long term outcome following transplantation is good, but immunosuppressive therapy can worsen the progression of associated kidney disease. Hepatocyte transplantation could be considered as a less invasive procedure in such patients. Our experience with hepatocyte transplantation in a 47 year-old woman affected by glycogen storage disease type Ia and suffering of severe fasting hypoglycaemia indicates that the procedure can partially correct some metabolic abnormalities and improve the quality of life in this disease. However, the metabolic improvement was reduced and finally abolished during long term follow-up, probably due to rejection or to senescence of transplanted cells. Moreover, the portal and pulmonary hypertension associated with the disease need to be evaluated for their possible influence on haemodynamic changes associated with cell infusion. Finally, hepatic adenomas need careful monitoring because of the possible risk of malignant transformation.

Neonatal bilirubin production-conjugation imbalance: effect of glucose-6-phosphate dehydrogenase deficiency and borderline prematurity

OBJECTIVE

To evaluate relations between production and conjugation of bilirubin in the pathophysiology of jaundice in glucose-6-phosophate dehydrogenase (G6PD) deficient neonates.

METHODS

Term and borderline premature (35-37 weeks gestational age), healthy, male, G6PD deficient neonates were studied close to the beginning of the 3rd day. Blood carboxyhaemogobin corrected for inspired CO (COHbc; an index of bilirubin production) and serum total conjugated bilirubin (TCB; a reflection of bilirubin conjugation) were measured in simultaneously drawn blood samples by gas chromatography and reverse phase high performance liquid chromatography respectively. A bilirubin production-conjugation index comprising COHbc/TCB was determined; a high index reflects imbalance between the bilirubin production and conjugation processes. COHbc and TCB individually and the production-conjugation index were studied in relation to serum total bilirubin (STB) concentration.

RESULTS

Fifty one G6PD deficient neonates were sampled at 51 (8) hours. COHbc values did not correlate with STB (r=0.22, p=0.15). TCB did correlate inversely with STB (r=-0.42, p=0.004), and there was a positive correlation between the production-conjugation index and STB (r=0.45, p=0.002). The production-conjugation index (median (interquartile range)) was higher in the premature (n=8) than term neonates (2.31 (2.12-3.08) v 1.05 (0.53-1.81), p=0.003). This difference was the result of changes in TCB.

CONCLUSIONS

The data show that jaundice in G6PD deficient neonates is the result of an imbalance between production and conjugation of bilirubin with a tendency for inefficient bilirubin conjugation over increased haemolysis in its pathogenesis. Borderline premature infants are at special risk of bilirubin production-conjugation imbalance.

Surface expression of squamous cell carcinoma antigen (SCCA) can be increased by the preS1(21-47) sequence of hepatitis B virus

A variant of the serpin squamous cell carcinoma antigen (SCCA) has been identified as a hepatitis B virus binding protein and high expression of SCCA has recently been found in hepatocarcinoma. Since HBV is involved in liver carcinogenesis, experiments were carried out to examine the effect of HBV preS1 envelope protein on SCCA expression. Surface and intracellular staining for SCCA was assessed by FACS analysis. Preincubation of HepG2 cells and primary human hepatocytes with preS1 protein or with preS1(21-47) tetrameric peptide significantly increased the surface expression of SCCA, without modification of its overall cellular burden, suggesting a surface redistribution of the serpin. An increase in HBV binding and internalization was observed after pre-incubation of the cells with preS1 preparations, compared to cells preincubated with medium alone. Pretreatment of cells with DMSO, while not influencing SCCA basal expression, was responsible for an increase in the efficiency of HBV internalization and this effect was additive to that obtained after incubation with preS1 preparations. In conclusion, the HBV preS1(21-47) sequence is able to induce overexpression of SCCA at the cell surface facilitating virus internalization, while the increased efficiency of HBV entry following DMSO addition is not mediated by SCCA.

Bilirubin inhibits bile acid induced apoptosis in rat hepatocytes

BACKGROUND AND AIMS

Hydrophobic bile acids contribute to hepatocellular injury in cholestasis and rapidly induce apoptosis in vitro; however, unlike Fas agonists, cholestasis does not cause extensive hepatocyte apoptosis. As antioxidants provide protection against bile acid induced liver injury, our premise was that bilirubin, a free radical scavenger with increased plasma levels in the presence of liver disease, could protect hepatocytes against bile acid induced apoptosis.

METHODS

Freshly isolated rat hepatocytes were incubated for four hours with 100 micromol/l glycochenodeoxycholate (GCDC) alone or with increasing concentrations of unconjugated (UCB) or conjugated (CB) bilirubin.

RESULTS

Both UCB and CB inhibited GCDC induced apoptosis in a dose dependent fashion and suppressed the generation of reactive oxygen species by hepatocytes.

CONCLUSIONS

The antiapoptotic effect of bilirubin associated with its antioxidant properties indicates that hyperbilirubinaemia may have a protective role in liver disease.

Serum bile acids in patients with liver failure supported with a bioartificial liver

BACKGROUND

Serum bile acids are increased in liver failure, but the composition of the bile acid pool in this condition has not been studied in detail. This information is of interest because of dihydroxy bile acid toxicity.

METHODS

We measured serum bile acids by gas chromatography-mass spectrometry in 13 patients with fulminant liver failure and five patients with acute-on-chronic liver failure. Furthermore, serum bile acids were analysed in the same patients after 6 h of treatment with a bioartificial liver, consisting of a hollow-fibre cartridge with microcarrier-attached porcine hepatocytes and a charcoal column.

RESULTS

Pre-bioartificial liver serum bile acids demonstrated a high dihydroxy/trihydroxy ratio and were higher in patients with acute-on-chronic liver failure than in those with fulminant liver failure (452.8 +/- 98.6 vs. 182.1 +/- 39.7 micro mol/L; P < 0.05). Bioartificial liver treatment decreased significantly serum bile acids in patients with fulminant liver failure (-38.8%) and acute-on-chronic liver failure (-35.8%), with a decreased dihydroxy/trihydroxy ratio. In vitro, porcine hepatocytes in the bioreactor cleared most conjugated bile acid species from pooled patient plasma.

CONCLUSIONS

Acute liver failure is associated with very high serum levels of toxic bile acids that could contribute to the pathogenesis of the syndrome. Bioartificial liver treatment reduces both serum bile acid concentrations and the hydrophobicity of the bile acid pool.

Prevalence and prognostic value of quantified electroencephalogram (EEG) alterations in cirrhotic patients

BACKGROUND/AIMS

The electroencephalogram (EEG) is frequently altered in cirrhotic patients. We, therefore, performed a study to ascertain the features and the prognosis of cirrhotic patients without current overt hepatic encephalopathy (OHE) who have EEG alterations.

METHODS

A series of 296 consecutive cirrhotic patients who had undergone quantified-EEG was studied. The median follow-up was 442 days, 128 patients had bouts of OHE and 78 patients died from liver-related causes. Another group of 124 cirrhotic patients with a median follow-up of 223 days was examined to validate the prognostic model.

RESULTS

EEG alterations were detected in 38% of the patients. The prevalence of EEG alterations was associated with the severity of cirrhosis (class B: odds ratio (OR) = 2.3, 95% confidence interval (CI) = 1.2-4.7; class C: OR = 3.5, 95% CI = 1.6-7.7), but not with the aetiology (alcoholic vs. non-alcoholic: OR = 0.9; 95% CI = 0.5-1.5). The EEG predicted the occurrence of OHE (chi2 = 26; P < 0.001) and mortality (chi2 = 34; P < 0.001), also adjusting for Child-Pugh class by a multivariate analysis. In the patients with a Child-Pugh score of > or = 8, the EEG discriminated between those patients with a higher 1-year risk of OHE (hazard ratio (HR) = 3.3, 95% CI = 1.8-6.1) and death (HR = 3.1, 95% CI = 1.7-5.6).

CONCLUSIONS

In conclusion, quantified-EEG had a prognostic value for the occurrence of bouts of OHE and mortality in cirrhotic patients.

Comparison of pig, human and rat hepatocytes as a source of liver specific metabolic functions in culture systems--implications for use in bioartificial liver devices

The limited availability of human hepatocytes results in the use of animal cells in most bioartificial liver support devices. In the present work, clinically relevant liver specific metabolic activities were compared in rat, pig and human hepatocytes cultured on liver-derived biomatrix to optimize the expression of differentiated functions. Pig hepatocytes showed higher rates of diazepam metabolism (2.549+/-0.821 microg/h/million cells vs. 0.474+/-0.079 microg/h/million cells rats, p<0.005, and vs. 0.704+/-0.171 microg/h/million cells in man, p<0.005) and of bilirubin conjugation (21.60116+/-8.433237 micromoles/l/24 h vs. 6.786809+/-2.983758 in man, p<0.001 and vs. 9.956538+/-1.781016 micromoles/l/24 h in rats, p<0.005). Urea synthesis was similar in pig and in human hepatocytes (150+/-46.3 vs. 144.8+/-21.46 nmoles/h/million cells) and it was lower in rats (84.38+/-35.2; p<0.001 vs. man, p<0.02 vs. pig). High liver specific metabolic activities in cultured pig hepatocytes further support their use as a substitue for human cells in bioartificial liver devices.

Unconjugated and conjugated bilirubin pigments during perinatal development. V. Effect of phototherapy on serum conjugated bilirubin in hyperbilirubinemic neonates

OBJECTIVE

To determine the effect of phototherapy on serum conjugated bilirubin fractions, an index of bilirubin conjugation, in hyperbilirubinemic neonates.

METHOD

Serum was sampled from 21 jaundiced (serum diazo total bilirubin > or = 274 micromol/l), term, otherwise healthy neonates prior to starting phototherapy, and 24 h after the commencement of treatment. Alkaline methanolysis followed by reverse-phase, high-performance liquid chromatography, specific for determination of unconjugated bilirubin and the monoconjugated and diconjugated fractions of total conjugated bilirubin in serum, was used for the analysis. Prephototherapy values were compared to those at 24 h.

RESULTS

Serum total bilirubin and total conjugated bilirubin values decreased during the study period, from 220 (211-239) to 177 (157-213) micromol/l (median (25-75% range)) p = 0.001, for the former, and from 1.4 (0.87-1.57) to 0.93 (0.69-1.84) micromol/l, p = 0.005, for the latter. These parameters decreased by a similar percentage (-16.6+/-14.8% and - 14.0+/-23.4%, respectively; p > 0.05). Both monoconjugated and diconjugated bilirubin, calculated as a percentage of total conjugated bilirubin, remained constant over the study period (88.2 (72.2-96.4)% before phototherapy and 92.5 (87.3-96.8)% after 24 h, p > 0.05, for monoconjugated bilirubin, and 11.8 (3.6-27.8)% and 7.5 (3.2-12.7)%, respectively, p > 0.05, for diconjugated bilirubin).

CONCLUSIONS

Serum total conjugated bilirubin values decreased in parallel to serum total bilirubin levels during phototherapy, maintaining a constant relationship between these two parameters. The ratios of monoconjugated and diconjugated bilirubin to total conjugated bilirubin remained constant. These findings imply that phototherapy does not alter bilirubin conjugation in hyperbilirubinemic neonates.

Unusual early presentation of Gilbert syndrome in pediatric recipients of liver transplantation

BACKGROUND

Gilbert syndrome as a rule becomes manifest in adolescence or in early adulthood; it may be transferred by the donor to orthotopic liver transplant (OLT) recipients.

METHODS

We examined the frequency of Gilbert syndrome in 46 OLT pediatric recipients who had a follow-up of 1 year or more. Diagnostic criteria included unexplained chronic or recurrent unconjugated hyperbilirubinemia; its increase after reduced caloric intake plus prolonged fasting, without changes of the proportion of conjugated bilirubin; and high relative amounts of serum unconjugated bilirubin IXa and prevalence of the monoglucuronide over the diglucuronide.

RESULTS

Of the 46 patients, 42 had normal bilirubin values. Only four otherwise healthy OLT recipients showed hyperbilirubinemia and normal conjugated fractions. Liver donors had been four men. Hyperbilirubinemia persisted with a fluctuating pattern for the whole follow-up after OLT in all. Total bilirubin level in blood samples obtained after reduced caloric intake and prolonged fasting became notably higher than basal values, whereas the proportion of conjugated bilirubin remained stable. High relative amounts of unconjugated bilirubin IXa and prevalence of the monoglucuronide over the diglucuronide were found. Finally, DNA from liver donors' lymphocytes was available for one jaundiced and two nonjaundiced patients: tests for abnormalities in the promoter region of the gene for the enzyme bilirubin uridine diphospho-glucuronosyltransferase were in agreement with a diagnosis of GS in the former one,

CONCLUSIONS

Gilbert syndrome may have an unusual early presentation in pediatric OLT recipients.

Standards for diagnosis of gastrointestinal motility disorders. Section: ultrasonography. A position statement from the Gruppo Italiano di Studio Motilità Apparato Digerente

Ultrasonography is a non-invasive, relatively easy, validated and reproducible technique. We assessed the usefulness of functional ultrasonography to study disorders of gastro-oesophageal tract, gallbladder and pancreatic duct. Oesophagus Oesophagus and the gastro-oesophageal junction can be visualized in children up to 5 years old. Ultrasonography shows 100% sensitivity and 87.5% specificity compared to ambulatory pH-metry for gastro-oesophageal reflux disease diagnosis. Stomach Ultrasonography can be used to estimate whole gastric volume, antral area or diameters, antro-pyloric volume, transpyloric flow in fasting state and in response to test meal. Gallbladder Ultrasonography is reliable to estimate volume in fasting state and in response to test meal or exogenous stimulus. For both stomach and gallbladder, indications might include the study of healthy subjects and of pathophysiologically relevant conditions such as dysmotility-like dyspepsia, suspicion of delayed gastric emptying, diabetes mellitus, gallstone disease and effect of drugs either delaying or accelerating motility. Common bile duct Ultrasonography can be used to estimate interprandial and postprandial common bile duct diameter in patients with clinical suspicion of common bile duct obstruction in fasting state and in response to test meal or exogenous stimuli. Although functional ultrasonography is used mainly for research purposes, its simplicity makes it appealing for clinical use to assess gastrointestinal motility in health and disease.

Bilirubin conjugation, reflected by conjugated bilirubin fractions, in glucose-6-phosphate dehydrogenase-deficient neonates: a determining factor in the pathogenesis of hyperbilirubinemia

BACKGROUND AND OBJECTIVE

Glucose-6-phosphate dehydrogenase (G-6-PD) deficiency is frequently associated with neonatal hyperbilirubinemia, which in severe cases may cause kernicterus and death. Because G-6-PD-deficient individuals frequently undergo acute, trigger-induced hemolytic episodes, increased hemolysis has frequently been implied in the pathogenesis of this neonatal hyperbilirubinemia. However, in Sephardic Jewish G-6-PD-deficient neonates, the rate of hemolysis, reflected by blood carboxyhemoglobin values corrected for inspired carbon monoxide, has been shown to be elevated, not only in those who developed hyperbilirubinemia, but also, to a similar extent, in those who remained only moderately jaundiced. Because at any point, serum total bilirubin values reflect a balance between bilirubin production on the one hand and bilirubin conjugation and elimination on the other, we suspected bilirubin conjugation to be a key factor in the pathogenesis of the hyperbilirubinemia. Physiologically, a fraction of conjugated bilirubin refluxes from the hepatocyte to the serum, and accurate determination of serum conjugated bilirubin fractions can be used to mirror intrahepatocytic bilirubin. Using this principle, we previously demonstrated a decreased diconjugated bilirubin fraction in hyperbilirubinemic G-6-PD-deficient neonates compared with hyperbilirubinemic G-6-PD-normal controls, suggesting diminished bilirubin conjugation. This conjugated bilirubin pattern probably reflects the recently described interaction between G-6-PD deficiency and the variant promoter for the gene encoding the bilirubin conjugating enzyme UDP glucuronosyltransferase, as seen in Gilbert's syndrome. Therefore, we postulated that efficiency of bilirubin conjugation is a crucial factor in the development of hyperbilirubinemia in G-6-PD-deficient neonates. We hypothesized that those G-6-PD-deficient neonates who develop hyperbilirubinemia would have decreased bilirubin conjugation ability, whereas those with a more efficient conjugating system would have a lesser degree of bilirubinemia.

METHODS

Term, healthy, male, G-6-PD-deficient neonates with no other obvious predisposing cause for hyperbilirubinemia were selected at random when their serum diazo total bilirubin values ranged from 171 to 254 micromol/L (10-14.9 mg/dL). At this point, simultaneous with the diazo bilirubin determination, serum was collected and frozen for high-performance liquid chromatography (HPLC) measurement of serum bilirubin fractions. The infants were followed clinically and with serum diazo bilirubin determinations until they either did not exceed a serum diazo bilirubin value of 254 micromol/L (14.9 mg/dL) (nonhyperbilirubinemic) or until bilirubin values rose above this level (hyperbilirubinemic), by a process of self-selection. A method of alkaline methanolysis, followed by reverse-phase HPLC, was used to measure unconjugated bilirubin and the mono- and diconjugated fractions of serum conjugated bilirubin. Total HPLC bilirubin and total conjugated bilirubin values were calculated from these measured bilirubin fractions. Patients also were classified according to the serum total conjugated bilirubin value as low bilirubin conjugators (serum total conjugated bilirubin less than median) or as high bilirubin conjugators (serum total conjugated bilirubin greater than median). The data were analyzed by comparing serum conjugated bilirubin fractions between the hyperbilirubinemic and nonhyperbilirubinemic groups and the risk of developing hyperbilirubinemia in the low bilirubin conjugators, relative to that of the high bilirubin conjugators.

RESULTS

Neonates were sampled at 53 +/- 12 and 58 +/- 12 hours for the subsequently hyperbilirubinemic and nonhyperbilirubinemic groups, respectively (NS). Initial (ie, at the time of sampling) serum total diazo bilirubin values (mean +/- SD) were almost identical for the subsequently hyperbilirubinemic and nonhyperbilirubinemic groups (214 +/

In chyloptysis, SP-A affects the clearance of serum lipoproteins entering the airways

Serum lipoproteins may enter the airways and appear in sputum (chyloptysis) when the lymphatic circulation is impaired by inflammation, neoplasia, or an abnormal proliferation of smooth muscle cells. While analyzing the bronchoalveolar lavage fluid of a patient with chyloptysis, we noticed that surfactant could not be separated from contaminating serum lipoproteins and speculated that lipoproteins might interact with surfactant components. To clarify this point we immobilized surfactant protein (SP) A on microtiter wells and incubated it with 125I-labeled very low density lipoproteins (VLDLs), low-density lipoproteins, and high-density lipoproteins. We found that SP-A binds lipoproteins. Studying in greater detail the interaction of SP-A with VLDLs, we found that the binding is time and concentration dependent; is inhibited by unlabeled lipoproteins, phospholipids, and antibodies to SP-A; is increased by Ca2+; and is unaffected by methyl alpha-D-mannopyranoside. Whole surfactant is a potent inhibitor of binding. Furthermore, we found that SP-A increases the degradation of VLDLs by alveolar macrophages and favors the association of VLDLs with alveolar surfactant. We conclude that SP-A influences the disposal of serum lipoproteins entering the airways and speculate that binding to alveolar surfactant might represent an important step in the interaction between exogenous substances and the lung.

Hepatocyte tight-junctional permeability is increased in rat experimental colitis

BACKGROUND & AIMS

Hepatobiliary complications occur in inflammatory bowel disease and may be caused by the translocation of intestinal toxins from portal blood into bile through leaky hepatocyte tight junctions. The role of tight junctions in the pathogenesis of hepatobiliary complications in experimental inflammatory bowel disease was investigated.

METHODS

Colitis was induced in rats by intracolonic instillation of trinitrobenzene sulfonic acid. The function of hepatocellular tight junctions was evaluated in perfused livers by measuring early (paracellular) horseradish peroxidase excretion into the bile and by electron microscopy and semiquantitative analysis of lanthanum penetration through the tight junction and into bile canaliculi. Immunofluorescent localization of cingulin and ZO-1 was used to study the structure of hepatocyte junctions.

RESULTS

Colitis was associated with increased serum bilirubin and bile acid concentrations, a 2.5-fold increase in paracellular biliary excretion of horseradish peroxidase, and a ninefold increase in lanthanum permeability. Liver histology and cingulin and ZO-1 localizations were similar to normal liver.

CONCLUSIONS

Experimental colitis is associated with hepatobiliary complications and an increased hepatocyte tight junctional permeability to horseradish peroxidase and lanthanum. Subtle alterations in tight junction function may be involved in the pathogenesis of hepatobiliary injuries in inflammatory bowel disease.

Is there a place for medical treatment in children with gallstones?

BACKGROUND

Medical treatment of gallstones with ursodeoxycholic acid (UDCA) or chenodeoxycholic acid (CDCA) has not been evaluated in children.

AIM

The purpose of this study was to assess the effectiveness of UDCA in the treatment of gallstones in children.

METHODS

UDCA was used to treat 15 patients, (7 boys and 8 girls; mean age, 7.8 years; range, 3 months to 15 years) for 1 year. All had radiolucent stones with a maximum diameter of 10 mm and a normally contractile gallbladder.

RESULTS

The stones disappeared completely in two children but returned later. All symptomatic patients became symptom free.

CONCLUSION

UDCA is ineffective in the treatment of gallstones in children except in terms of relieving symptoms while on treatment.

Prognostic value of the galactose test in predicting survival of patients with cirrhosis evaluated for liver transplantation. A prospective multicenter Italian study. AISF Group for the Study of Liver Transplantation. Associazione Italiana per lo Studio del Fegato

AIMS/METHODS

The present study aimed to examine whether the galactose elimination capacity can be used to predict the survival of patients with advanced liver disease. We studied 194 patients with cirrhosis, belonging to Child class B and C, for 2 years each.

RESULTS

The overall probability of survival was 79% at 6 months, 72% at 1 year and 62% at 2 years. Variables significantly associated with the duration of survival, as assessed by univariate analysis, were the Child-Pugh score, presence of ascites, size of esophageal varices, prothrombin time, albumin, bilirubin, urea, creatinine, glucose and galactose elimination capacity. By a multivariable analysis, only Pugh score (p = 0.005), creatinine (p < 0.001), varices (p = 0.001) and galactose elimination capacity (p < 0.001) were independent predictors of mortality. The galactose elimination capacity was even more sensitive when the end-point was limited to deaths due to liver failure and hepatorenal syndrome. A new score obtained by summing the Pugh score with a score derived from galactose elimination capacity was quite simple and accurate for predicting survival.

CONCLUSIONS

The quantitative measurement of liver function as the galactose elimination capacity could be of use to identify patients with cirrhosis and probable short survival who might benefit most from urgent transplantation.

Effect of withdrawal of pravastatin on biliary lipid composition in humans

Abrupt withdrawal of HMG-CoA reductase inhibitors is associated with increased excretion of cholesterol into bile, but this phenomenon has not been investigated in humans. In order to evaluate whether patients interrupting these hypolipidemic drugs are at increased risk of forming gallstones, pravastatin (40 mg twice a day) or placebo was randomly administered to 16 bile fistula patients for 5 days. Biliary lipid composition was determined in basal conditions and for 5 consecutive days after drug withdrawal. Both biliary cholesterol concentration and saturation increased significantly on the second day after pravastatin withdrawal, but tended to decrease thereafter. Biliary bile acids and phospholipids were not affected. This short-lasting effect on biliary cholesterol excretion was probably the result of a transient increase of hepatic cholesterol synthesis by the up-regulated HMG-CoA reductase in the absence of the inhibitory drug. These results are consistent with the hypothesis that, also in humans, biliary cholesterol excretion could be dependent on the hepatic free cholesterol pool.

Conjugated bilirubin in neonates with glucose-6-phosphate dehydrogenase deficiency

We used a system capable of measuring conjugated bilirubin and its monoconjugated and diconjugated fractions in serum to assess bilirubin conjugation in 29 glucose-6-phosphate dehydrogenase (G6PD)-deficient, term, male newborn infants and 35 control subjects; all had serum bilirubin levels > or = 256 mumol/L (15 mg/dI). The median value for diconjugated bilirubin was lower in the G6PD-deficient neonates than in control subjects (0.06 (range 0.00 to 1.84) vs 0.21 (range 0.00 to 1.02) mumol/L, p = 0.006). Diglucuronide was undetectable in 11 (38.9%) of the G6PD-deficient infants versus 3 (8.6%) of the control subjects (p = 0.015). These findings imply a partial defect of bilirubin conjugation not previously demonstrated in G6PD-deficient newborn infants.

Ultrasonic evaluation of gallbladder emptying with ceruletide

In order to develop a practical and reproducible method to assess gallbladder function, gallbladder emptying was studied by ultrasound in 27 gallstone patients after i.m. administration of ceruletide (0.3 micrograms/kg), and the procedure was compared to oral cholecystography with fatty meal. Maximal percent gallbladder contraction was reached in all patients 30 min after ceruletide. Maximal percent contractions were 47.5 +/- 27.7 during ultrasound with ceruletide and 33.9 +/- 16.3 during oral cholecystography with fatty meal (p = 0.03). A significant linear relationship was found between the results obtained with the two different procedures (r = 0.57; p = 0.002). Serial ultrasound determinations of gallbladder emptying were performed in 16 patients. Day-to-day variation was below 20% in 11 subjects, and it ranged between 20 and 40% in 5 subjects. Minor side effects were observed in 9 patients. Ultrasound determination of gallbladder emptying after ceruletide appears to be a practical and reliable method to assess gallbladder function.

Effect of tauroursodeoxycholic acid (TUDCA) on biliary lipid composition

TUDCA has been proposed in the treatment of hepatobiliary disease, but data on the enrichment of the biliary TUDCA pool and changes of biliary lipids after administration of the compound are scarce. We studied the composition of biliary lipids in a series of 33 patients with radiolucent stones, before and after treatment with TUDCA, 3.5 to 16.6 mg/kg/die for 4-6 weeks. Duodenal bile was collected with the Entero-Test after gallbladder contraction. Cholesterol saturation was 147% + 67 before treatment. TUDCA administration produced the following dose-dependent effects: a) a linear decrease of cholesterol saturation (r = 0.59; p); b) a non-linear increase of the percent of ursodeoxycholate in bile (r = 0.59; p); c) a non-linear increase of the fraction of ursodeoxycholate conjugated with taurine. At the dose of 11 mg/kg per day, cholesterol saturation was 80%, ursodeoxycholic acid represented about 45% of biliary bile acids, and about half of urso was conjugated with taurine. These results can be used as guidelines to assess the required daily dosage of TUDCA.

Effect of tauroursodeoxycholic acid on biliary lipid composition. A dose-response study

Tauroursodeoxycholic acid has been proposed for the treatment of hepatobiliary disease, but data on the enrichment of biliary tauroursodeoxycholic acid pool and on changes of biliary lipids after administration of the compound are scarce. We studied the composition of biliary lipids in a series of 33 patients with radiolucent stones, before and after treatment with tauroursodeoxycholic acid, 3.5 - 16.6 mg/kg/day for 4 - 6 weeks. Duodenal bile was collected with the Entero-Test after gallbladder contraction. Tauroursodeoxycholic acid administration produced the following dose-dependent effects: a linear decrease of cholesterol saturation (r = 0.59, p < 0.001); a non-linear increase of the percent of ursodeoxycholic acid in bile (r = 0.59, p < 0.001); a non-linear increase of the fraction of ursodeoxycholate conjugated with taurine. At the dose of 11 mg/kg per day, cholesterol saturation was 80%, ursodeoxycholic acid represented about 45% of biliary bile acids, and about half of UDCA was conjugated with taurine. Biliary bile acids were repeatedly measured in 6 patients during long-term treatment with 9.7 - 12.1 mg/kg. The fraction of tauroursodeoxycholic acid decreased progressively from 67.6% +/- 10.5 to 29.1% +/- 5. Tauroursodeoxycholic acid is as effective as ursodeoxycholic acid on a molar basis in reducing biliary cholesterol saturation and in enriching bile with ursodeoxycholate. Moreover, tauroursodeoxycholic acid administration is associated with higher concentrations of tauroconjugates in the bile than those previously reported by feeding the free bile acid.

Serum and bile bilirubin pigments in the differential diagnosis of Crigler-Najjar disease

OBJECTIVE

To differentiate between Crigler-Najjar (CN) disease types 1 and 2.

DESIGN

The patterns of serum bilirubins, bile pigment composition, and phenobarbital response were studied.

PATIENTS

Three infants, affected by high serum unconjugated bilirubin concentrations, previously classified as type 1 CN.

METHODS

Serum and bile bilirubin pigment composition, both before and after phenobarbital (PB) treatment, were determined by alkaline methanolysis and high-pressure liquid chromatography. PB was given for at least 3 weeks by oral administration (5 mg/kg bw per day).

RESULTS

No diconjugated bilirubin was found either before or after PB treatment in the serum of the three studied infants. In two patients traces of monoconjugated bilirubin were detected before PB therapy, and the ratio of conjugated/total bilirubin (percent) was increased by the PB response. In the third patient, traces of monoconjugated bilirubin appeared only after PB administration. However, the serum unconjugated bilirubin concentration decreased significantly only in the second patient, following the second cycle of PB treatment, leading to the diagnosis of type 2 CN. The analysis of the methyl ester derivatives of bile pigments was also performed on bile samples obtained in two patients by Entero-Test (R) both before and after PB treatment. An absolute increment in monoesterified bilirubin concentration was found after PB administration, although the percent concentration increased in one case and decreased in the other. No diesterified bilirubin was detected in the bile samples.

CONCLUSIONS

The present results show that in types 1 and 2 CN disease it is possible to detect traces of monoconjugated but not diconjugated bilirubin both in serum and in bile. Whereas PB treatment is effective in slightly increasing the serum monoconjugated bilirubin concentration even in type 1 CN disease, the diagnosis of type 1 or 2 is based on finding a substantial decrease of serum unconjugated bilirubin following PB administration.

Ultrasonic evaluation of gallbladder emptying with ceruletide: comparison to oral cholecystography with fatty meal

Assessment of gallbladder function is required prior to nonsurgical treatment of gallstones. In order to develop a practical and reproducible method of evaluation, gallbladder emptying was studied by ultrasound (US) in 55 gallstone patients after intramuscular administration of ceruletide (0.3 micrograms/kg). In 27 of these subjects, the US procedure was compared to oral cholecystography (OCG) with fatty meal. Maximal percent gallbladder contraction was reached 30 min after ceruletide in all patients. Maximal percent contractions were 47.5 +/- 27.7 during US with ceruletide and 33.9 +/- 16.3 during OCG with fatty meal (p = 0.03). A significant linear relationship was found between the results obtained with the two different procedures (r = 0.57; p = 0.002). Serial US determinations of gallbladder emptying were performed in 16 patients. Individual variation was below 20% in 11 subjects, and in five subjects it ranged between 20 and 40%. Minor, self-limiting side effects were observed in 13 patients. US determination of gallbladder emptying after ceruletide appears to be a practical and reliable method to assess gallbladder function.

Serum bile acids and esterified bilirubin in early detection and differential diagnosis of hepatic dysfunction following orthotopic liver transplantation

Routine laboratory tests are of little help for early detection and differential diagnosis of hepatic dysfunction following orthotopic liver transplantation (OLT). In the present study, serum levels of esterified bilirubin, total bilirubin and bile acids were investigated in 20 patients after OLT. Twenty episodes of liver dysfunction were observed: 10 rejection episodes, 3 cases of thrombosis of the hepatic artery, 3 cases of septic shock, and 4 episodes of cyclosporin toxicity. During rejection, the median increase in esterified bilirubin was 3.2-fold (range 1.6-24.9), while total bilirubin increased 1.5-fold (range 0.7-3.4). Bile acids increased 3.6-fold (range 2.5-6.6; peak levels 25-87 microM). Both bile acids and esterified bilirubin increased 1-3 days earlier than serum transaminases and decreased only after successful anti-rejection treatment. The response of bile acids to successful treatment was usually more rapid than the response of esterified bilirubin. Hepatic artery thrombosis and septic shock were associated with a sharp increase in esterified bilirubin and very high bile acid levels (peak levels 80-185 microM). During cyclosporin toxicity, a characteristic pattern of progressively increasing bilirubin with no change in the bile acid levels was observed. Both esterified bilirubin and bile acids are very sensitive indicators of hepatic graft dysfunction. In particular, serum bile acids are useful for identifying cyclosporin toxicity and monitoring the response to anti-rejection treatment.

Alterations in bilirubin metabolism during extra- and intrahepatic cholestasis

This study was performed to investigate modifications in the serum bilirubin forms, hepatobiliary enzymes, and some glycoproteic substances in patients during the course of extrahepatic cholestasis (stage A) and following its clinical resolution (stage B). The series consisted of 16 patients: 11 had main bile duct stones; two, benign stenosis of the main bile duct; and three, main bile duct cancer. Cholestasis resolved spontaneously in one case, under endoscopy in two, and following surgery in 13. Five patients with liver cirrhosis and a picture of intrahepatic cholestasis following anesthesia were also investigated. Serum bilirubin forms were measured using van den Bergh's method and the alkaline methanolysis-HPLC procedure; the mono- and di-conjugated forms were considered together in the overall evaluation of the results. The hepatobiliary enzymes (ALP, GGT, and AST) were increased at stage A and significantly decreased at stage B. Similar patterns were observed in total (TB), unconjugated (UB), and conjugated bilirubin (CB) and in the percentage of CB out of TB (% CB). In the majority of patients, % CB at stage B was lower than at stage A, whereas in subjects with a high initial UB value, a different % CB pattern was observed. The direct bilirubin percentage (% DB), on the other hand, had a different pattern, and the variations between stages A and B were not significant. The pathophysiological bilirubin pattern was similar in patients with intrahepatic cholestasis. At stage A, in a number of patients the levels of glycoproteic substances (CA 19-9, TPA and ferritin) were raised, but at stage B they tended to decrease towards the normal range.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of Silibinin on biliary lipid composition. Experimental and clinical study

The effect of Silymarin, a natural flavonoid, on biliary lipid composition, was studied in rats and humans. Bile flow, biliary cholesterol, phospholipid and total bile salt concentrations were measured in 23 control rats and in 27 rats treated with Silibinin, the active component of Silymarin, at the dose of 100 mg/kg body weight i.p. (n = 21) or 50 mg/kg body weight i.p. (n = 6) for 7 days. Biliary cholesterol and phospholipid concentrations were significantly reduced after the higher Silibinin dose (60.9 and 72.9% of the control values), whereas bile flow and biliary total bile salt concentration were unchanged. After the lower Silibinin dose all parameters remained unchanged. Total liver cholesterol content was not affected by Silibinin. On the other hand, in vitro determination of rat liver microsomal 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase activity showed a significant dose-dependent inhibition by Silibinin (0.5-8 mg/kg). Biliary lipid composition was also assayed in four gallstone and in 15 cholecystectomized patients before and after Silymarin (420 mg per day for 30 days) or placebo administration. In both groups, biliary cholesterol concentrations were reduced after Silymarin treatment and the bile saturation index significantly decreased accordingly. These data suggest that Silibinin-induced reduction of biliary cholesterol concentration both in humans and in rats might be, at least in part, due to a decreased synthesis of liver cholesterol.