Diagnostic performance of FibroTest, SteatoTest and ActiTest in patients with NAFLD using the SAF score as histological reference

BACKGROUND

Blood tests of liver injury are less well validated in non-alcoholic fatty liver disease (NAFLD) than in patients with chronic viral hepatitis.

AIMS

To improve the validation of three blood tests used in NAFLD patients, FibroTest for fibrosis staging, SteatoTest for steatosis grading and ActiTest for inflammation activity grading.

METHODS

We pre-included new NAFLD patients with biopsy and blood tests from a single-centre cohort (FibroFrance) and from the multicentre FLIP consortium. Contemporaneous biopsies were blindly assessed using the new steatosis, activity and fibrosis (SAF) score, which provides a reliable and reproducible diagnosis and grading/staging of the three elementary features of NAFLD (steatosis, inflammatory activity) and fibrosis with reduced interobserver variability. We used nonbinary-ROC (NonBinAUROC) as the main endpoint to prevent spectrum effect and multiple testing.

RESULTS

A total of 600 patients with reliable tests and biopsies were included. The mean NonBinAUROCs (95% CI) of tests were all significant (P < 0.0001): 0.878 (0.864-0.892) for FibroTest and fibrosis stages, 0.846 (0.830-0.862) for ActiTest and activity grades, and 0.822 (0.804-0.840) for SteatoTest and steatosis grades. FibroTest had a higher NonBinAUROC than BARD (0.836; 0.820-0.852; P = 0.0001), FIB4 (0.845; 0.829-0.861; P = 0.007) but not significantly different than the NAFLD score (0.866; 0.850-0.882; P = 0.26). FibroTest had a significant difference in median values between adjacent stage F2 and stage F1 contrarily to BARD, FIB4 and NAFLD scores (Bonferroni test P < 0.05).

CONCLUSIONS

In patients with NAFLD, SteatoTest, ActiTest and FibroTest are non-invasive tests that offer an alternative to biopsy, and they correlate with the simple grading/staging of the SAF scoring system across the three elementary features of NAFLD: steatosis, inflammatory activity and fibrosis.

Moderate alcohol use and health: a consensus document

AIMS

The aim of this consensus paper is to review the available evidence on the association between moderate alcohol use, health and disease and to provide a working document to the scientific and health professional communities.

DATA SYNTHESIS

In healthy adults and in the elderly, spontaneous consumption of alcoholic beverages within 30 g ethanol/d for men and 15 g/d for women is to be considered acceptable and do not deserve intervention by the primary care physician or the health professional in charge. Patients with increased risk for specific diseases, for example, women with familiar history of breast cancer, or subjects with familiar history of early cardiovascular disease, or cardiovascular patients should discuss with their physician their drinking habits. No abstainer should be advised to drink for health reasons. Alcohol use must be discouraged in specific physiological or personal situations or in selected age classes (children and adolescents, pregnant and lactating women and recovering alcoholics). Moreover, the possible interactions between alcohol and acute or chronic drug use must be discussed with the primary care physician.

CONCLUSIONS

The choice to consume alcohol should be based on individual considerations, taking into account the influence on health and diet, the risk of alcoholism and abuse, the effect on behaviour and other factors that may vary with age and lifestyle. Moderation in drinking and development of an associated lifestyle culture should be fostered.

ASH and NASH

Non-alcoholic steatohepatitis (NASH) and alcoholic steatohepatitis (ASH) have a similar pathogenesis and histopathology but a different etiology and epidemiology. NASH and ASH are advanced stages of non-alcoholic fatty liver disease (NAFLD) and alcoholic fatty liver disease (AFLD). NAFLD is characterized by excessive fat accumulation in the liver (steatosis), without any other evident causes of chronic liver diseases (viral, autoimmune, genetic, etc.), and with an alcohol consumption ≤20-30 g/day. On the contrary, AFLD is defined as the presence of steatosis and alcohol consumption >20-30 g/day. The most common phenotypic manifestations of primary NAFLD/NASH are overweight/obesity, visceral adiposity, type 2 diabetes, hypertriglyceridemia and hypertension. The prevalence of NAFLD in the general population in Western countries is estimated to be 25-30%. The prevalence and incidence of NASH and ASH are not known because of the impossibility of performing liver biopsy in the general population. Up to 90% of alcoholics have fatty liver, and 5-15% of these subjects will develop cirrhosis over 20 years. The risk of cirrhosis increases to 30-40% in those who continue to drink alcohol. About 10-35% of alcoholics exhibit changes on liver biopsy consistent with alcoholic hepatitis. Natural histories of NASH and ASH are not completely defined, even if patients with NASH have a reduced life expectancy due to liver-related death and cardiovascular diseases. The best treatment of AFLD/ASH is to stop drinking, and the most effective first-line therapeutic option for NAFLD/NASH is non-pharmacologic lifestyle interventions through a multidisciplinary approach including weight loss, dietary changes, physical exercise, and cognitive-behavior therapy.

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.

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.

The role of contrast-enhanced ultrasound in detection of liver metastases from colorectal cancer: A prospective monocentric study

e15105

Background: Up to 15–25% of patients with colorectal cancer (CRC) will develop metacronous liver metastases during the follow up. The management and prognosis of these patients depend heavily on the early detection of metastases. The most effective surveillance strategy has not yet being extablished. The introduction of second generation ultrasound contrast agents have improved the ability of contrast-enhanced ultrasound (CEUS) in detecting and characterizing liver lesions, showing that its accuracy is comparable to that of spiral CT and MRI with a liver contrast agent, with a cost and a time saving. We tested the sensitivity and specificity of CEUS in detecting liver metastases compared with the standard imaging modalities used in the follow up of CRC. Methods: We conducted a prospective study considering all patients with a diagnosis of CRC in high risk stage II, stage III or with a previous metastasectomy of the liver. In order to detect possible metastases, the patients were followed with a follow-up schedule including a six-monthly ultrasonography alternated to an annual CT, and a six-monthly CEUS with SonoVue contrast agent for the first 3 years. Results: From January 1st to December 2008 we executed 60 CEUS, identifying thirteen suspected liver lesions. 10/13 were confirmed metastases by CT, MRI or TC/PET. 2/13 resulted benign lesions. 1/13 resulted negative at the CT but positive with a MRI. Another additional case was missed by CEUS but detected by CT. CEUS improve specificity and sensitivity compared with baseline ultrasonography. We had an histological confirmation in all cases except one. The study is still recruiting patients. Conclusions: The clinical value of CEUS as a reliable alternative to CT or MRI in characterizing focal liver lesions has been expressed in various documents and guidelines. Our preliminary results confirm the similar diagnostic performance and confidence of CEUS compared to these imaging modalities in the follow up of CRC. Further clinical studies are still needed to strenghten the existing data.

No significant financial relationships to disclose.

Non-alcoholic fatty liver disease (NAFLD) and cardiovascular disease: an open question

AIMS

To review available data concerning the basic science and epidemiological-clinical evidence for an association of NAFLD and cardiovascular disease.

DATA SYNTHESIS

Non-alcoholic fatty liver disease (NAFLD) defines alcohol-like hepatic histological lesions seen in the non-alcoholic, insulin resistant patient representing the hepatic counterpart of the metabolic syndrome. Along with insulin resistance, additional genetic, endocrine and vascular changes together with environmental stimuli--which are also involved in the pathogenesis of atherosclerosis--play a prominent role in the development and progression of NAFLD. Clinical and epidemiological studies seem to indicate that NAFLD is associated with an increased risk for cardiovascular disease but further studies are needed to confirm the available data. The mainstay of NAFLD treatment is based on the correction of the same metabolic changes that predispose to atherosclerosis.

CONCLUSIONS

Non-invasive evaluation of risk for cardiovascular events is recommended in all individuals presenting with NAFLD and conversely, the presence of NAFLD should always be looked for in subjects with features belonging to the metabolic syndrome. Further studies are needed on the mechanisms linking fatty liver and vascular diseases.

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.

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.

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.

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.

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.

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.

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.

Prevalence of and risk factors for hepatic steatosis in Northern Italy

BACKGROUND

Although hepatic steatosis is seen with increasing frequency in clinical practice, its prevalence and risk factors are unknown.

OBJECTIVE

To investigate the prevalence of and risk factors for hepatic steatosis, such as alcohol consumption and obesity.

DESIGN

Cross-sectional, observational study.

SETTING

Participants in the Dionysos Study.

PATIENTS

257 participants assigned to one of four categories (67 controls, 66 obese persons, 69 heavy drinkers, and 55 obese heavy drinkers).

MEASUREMENTS

Ethanol intake, assessed by a validated questionnaire and expressed as daily (g/d) and lifetime (kg) consumption, and body mass, expressed as body mass index. Biochemical tests of liver and metabolic function and hepatic ultrasonography were done.

RESULTS

The prevalence of steatosis was increased in heavy drinkers (46.4% [95% CI, 34% to 59%]) and obese persons (75.8% [CI, 63% to 85%]) compared with controls (16.4% [CI, 8% to 25%]). Steatosis was found in 94.5% (CI, 85% to 99%) of obese heavy drinkers. Compared with controls, the risk for steatosis was higher by 2.8-fold (CI, 1.4-fold to 7.1-fold) in heavy drinkers, 4.6-fold (CI, 2.5-fold to 11.0-fold) in obese persons, and 5.8-fold (CI, 3.2-fold to 12.3-fold) in persons who were obese and drank heavily. In heavy drinkers, obesity increased the risk for steatosis by twofold (CI, 1.5-fold to 3.0-fold) (P < 0.001), but heavy drinking was associated with only a 1.3-fold (CI, 1.02-fold to 1.6-fold) increase in risk in obese persons (P = 0.0053). Elevated alanine aminotransferase and triglyceride levels are the most reliable markers of steatosis.

CONCLUSIONS

Steatosis is frequently encountered in healthy persons and is almost always present in obese persons who drink more than 60 g of alcohol per day. Steatosis is more strongly associated with obesity than with heavy drinking, suggesting a greater role of overweight than alcohol consumption in accumulation of fat in the liver.

Prevalence of and risk factors for hepatic steatosis in Northern Italy

BACKGROUND

Although hepatic steatosis is seen with increasing frequency in clinical practice, its prevalence and risk factors are unknown.

OBJECTIVE

To investigate the prevalence of and risk factors for hepatic steatosis, such as alcohol consumption and obesity.

DESIGN

Cross-sectional, observational study.

SETTING

Participants in the Dionysos Study.

PATIENTS

257 participants assigned to one of four categories (67 controls, 66 obese persons, 69 heavy drinkers, and 55 obese heavy drinkers).

MEASUREMENTS

Ethanol intake, assessed by a validated questionnaire and expressed as daily (g/d) and lifetime (kg) consumption, and body mass, expressed as body mass index. Biochemical tests of liver and metabolic function and hepatic ultrasonography were done.

RESULTS

The prevalence of steatosis was increased in heavy drinkers (46.4% [95% CI, 34% to 59%]) and obese persons (75.8% [CI, 63% to 85%]) compared with controls (16.4% [CI, 8% to 25%]). Steatosis was found in 94.5% (CI, 85% to 99%) of obese heavy drinkers. Compared with controls, the risk for steatosis was higher by 2.8-fold (CI, 1.4-fold to 7.1-fold) in heavy drinkers, 4.6-fold (CI, 2.5-fold to 11.0-fold) in obese persons, and 5.8-fold (CI, 3.2-fold to 12.3-fold) in persons who were obese and drank heavily. In heavy drinkers, obesity increased the risk for steatosis by twofold (CI, 1.5-fold to 3.0-fold) (P < 0.001), but heavy drinking was associated with only a 1.3-fold (CI, 1.02-fold to 1.6-fold) increase in risk in obese persons (P = 0.0053). Elevated alanine aminotransferase and triglyceride levels are the most reliable markers of steatosis.

CONCLUSIONS

Steatosis is frequently encountered in healthy persons and is almost always present in obese persons who drink more than 60 g of alcohol per day. Steatosis is more strongly associated with obesity than with heavy drinking, suggesting a greater role of overweight than alcohol consumption in accumulation of fat in the liver.

Prevalence of non-organ-specific autoantibodies and chronic liver disease in the general population: a nested case-control study of the Dionysos cohort

BACKGROUND

Several retrospective and prospective studies report an increased prevalence of non-organ-specific autoantibodies (NOSAs) in patients with hepatitis C virus (HCV) related chronic liver disease (CLD). Some of the data so far available are controversial and the true prevalence of NOSAs in the general population is still not known.

AIM

To explore the prevalence of NOSAs, their relation to different HCV genotypes, and the presence and severity of CLD in the general population of Northern Italy.

PATIENTS

All 226 anti-HCV positive and 87 hepatitis B surface antigen (HBsAg) positive patients of the Dionysos cohort study were analysed and compared with sex and age matched cases (226) negative for both anti-HCV antibody and HBsAg selected from the same cohort.

METHODS

Sera tested for the presence of NOSAs (anti-nuclear antibody (ANA), anti-smooth muscle antibody (SMA), and anti-liver/kidney microsomes type 1 antibody (LKM1)) were screened by indirect immunofluorescence at a 1:40 serum dilution. HCV RNA and HCV genotypes were also determined by nested polymerase chain reaction (PCR) of the 5' non-coding region and by PCR amplification of the core region with type specific primers.

RESULTS

The overall prevalence of NOSA reactivity was significantly higher in anti-HCV positive subjects than in both normal and pathological controls (25% v 6% and 7% respectively, p<0.05). ANA, SMA, and LKM1 occurred in 16, 10, and 1. 3% of cases respectively. No specific association between NOSAs and a specific HCV genotype was found. NOSAs were found more often associated with more than one genotype (35.7%) and with untypable genotypes (34.6%), although the association was not statistically significant. NOSAs were associated with HCV RNA and CLD but not with the presence of cirrhosis and/or hepatocellular carcinoma. On univariate analysis, NOSA reactivity was independently associated with abnormal alanine aminotransferase (p<0.01) and gamma-glutamyltranspeptidase levels (p<0.05). The risk for the presence of NOSAs was 5.1 times higher in anti-HCV subjects than in controls.

CONCLUSIONS

In the general population the prevalence of NOSAs is higher in anti-HCV positive subjects than in normal or disease controls. Moreover NOSAs are associated with CLD and with a more active disease in terms of alanine aminotransferase activity.

Familial clustering of Helicobacter pylori infection: population based study

OBJECTIVES

To assess the rate of intrafamilial transmission of Helicobacter pylori infection in the general population and the role of a family's social background.

DESIGN

Population survey.

SETTING

Campogalliano, a town in northern Italy with about 5000 residents.

PARTICIPANTS

3289 residents, accounting for 416 families.

MAIN OUTCOME MEASURES

Prevalence of H pylori infection assessed by presence of IgG antibodies to H pylori.

RESULTS

The overall prevalence of H pylori infection was 58%. Children belonging to families with both parents infected had a significantly higher prevalence of H pylori infection (44%) than children from families with only one (30%) or no parents (21%) infected (P<0.001). Multivariate analyses confirmed that children with both parents positive had double the risk of being infected by H pylori than those from families in which both parents were negative. Family social status was independently related to infection in children, with those from blue collar or farming families showing an increased risk of infection compared with children of white collars workers (odds ratio 2.02, 95% confidence interval 1.16 to 3.49).

CONCLUSIONS

H pylori infection clusters within families belonging to the same population. Social status may also be a risk factor. This suggests either a person to person transmission or a common source of exposure for H pylori infection.

Clinical course and risk factors of hepatitis C virus related liver disease in the general population: report from the Dionysos study

BACKGROUND

The severity, clinical course, and risk of hepatitis C virus (HCV) related chronic liver disease are still rather poorly defined.

AIMS

To investigate the prevalence, risk factors, and severity of HCV related liver disease in the general population, and investigate whether infection with a specific genotype is associated with an increased risk of cirrhosis or hepatocellular carcinoma.

METHODS

HCV RNA determination by polymerase chain reaction (PCR) and HCV genotyping were performed in all anti-HCV positive subjects belonging to the Dionysos study (6917 subjects). Diagnosis of cirrhosis and hepatocellular carcinoma was established by liver biopsy in all cases. All the data were analysed by univariate and multivariate statistics in all the cohort. To investigate the natural history of HCV infection, anti-HCV positive subjects were followed up every six months for three years with liver function tests and ultrasonograms.

RESULTS

The overall prevalence of HCV RNA positivity was 2.3%. Positivity increased progressively with age, and was higher in women (ratio of men to women = 0.7). Genotypes 1b and 2a were the most frequent (42 and 24% of HCV RNA positive patients), with a prevalence of 1 and 0.6% respectively. Intravenous drug use, blood transfusions received before 1990, history of previous hepatitis among the cohabiting, and history of animal (mainly dogs) bites were significantly (p<0.05) associated with HCV infection, independently of age and sex. Multivariate analysis showed that, independently of age, sex, and alcohol intake, genotype 1b infection, with or without coinfection with other genotypes, is the major risk factor associated with the presence of cirrhosis and/or hepatocellular carcinoma. During the three years of follow up, 57 (35%) of the HCV RNA positive subjects had consistently normal alanine aminotransferase and gamma-glutamyltransferase values. Two of the 22 HCV RNA positive cirrhotic patients, all drinking more than 90 g of alcohol a day, developed hepatocellular carcinoma (incidence rate = 3.0% per year).

CONCLUSIONS

In the general population of Northern Italy, HCV infection is widespread, but only less than 50% of the anti-HCV positive subjects, particularly those infected with genotype 1b, are associated with a more severe liver disease. Alcohol consumption greater that 30 g a day significantly aggravates the natural course of the disease.

Role of cytokines in ethanol-induced cytotoxicity in vitro in Hep G2 cells

BACKGROUND & AIMS

As shown previously by us, ethanol (EtOH) causes time- and concentration-dependent reduction in cytoviability. Tauroursodeoxycholic acid (TUDCA) and ursodeoxycholic acid (UDCA) were shown to reduce cytotoxicity. Long-term EtOH exposure leads to immunoregulatory and detoxification impairment. This study aimed to determine the relationship between cytokine (interleukin [IL]-1 alpha and IL-6 and tumor necrosis factor [TNF]-alpha) production and expression, glutathione (GSH) status, and EtOH-induced cytotoxicity on Hep G2 cells.

METHODS

Cells were incubated with 80 mmol/L EtOH or alpha-minimal essential medium (control) in the presence or absence of 50 mumol/L TUDCA or UDCA. Cytokine release was quantitated by enzyme-linked immunosorbent assay. Cytokine expression was measured by reverse-transcription polymerase chain reaction. GSH content was determined in both the cytosolic and mitochondrial fractions.

RESULTS

After 24 hours of EtOH exposure, the release of IL-1 alpha doubled, that of IL-6 increased 10 times, and that of TNF-alpha increased 3.5 times. Cytokine expression was up-regulated compared with control for IL-1 alpha (42%), IL-6 (26%), and TNF-alpha (52%). Addition of 50 mumol/L TUDCA or UDCA reduced cytokine release and expression. TNF-alpha increased cytotoxicity by 18%. Anti-TNF-alpha antibody almost abolished it. EtOH depleted mGSH levels by 55% (P < 0.001). TUDCA replenished them by 88%.

CONCLUSIONS

EtOH up-regulated expression of cytokines in Hep G2 cells is down-regulated by bile acids. Increased amounts of TNF-alpha and depletion in both cytosolic and mitochondrial GSH contribute to EtOH cytotoxicity. Bile acids prevent toxicity.

Drinking habits as cofactors of risk for alcohol induced liver damage. The Dionysos Study Group

BACKGROUND

The Dionysos Study is a cohort study of the prevalence of chronic liver disease in the general population of two northern Italian communities. It included 6917 subjects, aged 12-65 (69% of the total population).

AIMS

The aim of this part of the study was to examine the relationship of daily alcohol intake, type of alcoholic beverage consumed, and drinking patterns to the presence of alcohol induced liver damage in an open population.

PATIENTS AND METHODS

6534 subjects, free of virus related chronic liver disease and participating in the first cross-sectional part of the study, were fully examined. Each subject underwent: (a) medical history and physical examination, (b) evaluation of alcohol intake using an illustrated dietary questionnaire, and (c) routine blood tests. More invasive diagnostic procedures were performed when indicated.

RESULTS

Multivariate analysis showed that the risk threshold for developing either cirrhosis or non-cirrhotic liver damage (NCLD) was ingestion of more than 30 g alcohol per day in both sexes. Using this definition, 1349 individuals (21% of the population studied) were at risk. Of these, only 74 (5.5% of the individuals at risk) showed signs of liver damage. The prevalence of "pure" alcoholic cirrhosis was 0.43% (30 of 6917), representing 2.2% of the individuals at risk, with a ratio of men to women of 9:1, while 44 (3.3% of the individuals at risk) showed persistent signs of NCLD. After 50 years of age, the cumulative risk of developing both NCLD and cirrhosis was significantly higher (p < 0.0001) for those individuals who regularly drank alcohol both with and without food than for those who drank only at mealtimes.

CONCLUSIONS

Our data show that in an open population the risk threshold for developing cirrhosis and NCLD is 30 g ethanol/day, and this risk increases with increasing daily intake. Drinking alcohol outside mealtimes and drinking multiple different alcoholic beverages both increase the risk of developing alcohol induced liver damage.

Chronic administration of ursodeoxycholic and tauroursodeoxycholic acid changes microsomal membrane lipid content and fatty acid compositions in rats

We studied the effect of oral supplementation with ursodeoxycholate (UDCA) or tauroursodeoxycholate (TUDCA) on the lipid content and fatty acid composition of rat hepatic microsomes. UDCA and TUDCA significantly increased the total amount of lipids with the exception of cholesteryl-esters. UDCA significantly increased the triglycerides and phosphatidylethanolamine (PE) microsomal content, and decreased the cholesterol/phospholipids and the phosphatidylcholine (PC)/PE ratio. Both treatments increased the percentage oleic acid and of polyunsaturated fatty acids (PUFA) in each class of lipids. UDCA and TUDCA had a different action on PUFA microsomal molar percentage of phospholipids: UDCA increased the relative percentage of PUFA in the PE fraction, while TUDCA increased the relative percentage of PUFA in the PC fraction. These changes in the hepatic lipid content and composition might in part explain both cytoprotective action of these hydrophillic bile acids and their effect on membrane fluidity.

Effect of tauroursodeoxycholic and ursodeoxycholic acid on ethanol-induced cell injuries in the human Hep G2 cell line

BACKGROUND & AIMS

Taurodeoxycholic acid (TUDCA) and ursodeoxycholic acid (UDCA) exert a protective effect in chronic cholestasis. This study reports the effect of TUDCA and UDCA on an in vitro model for ethanol-induced liver damage.

METHODS

Hep G2 cells were incubated for 24 hours with 80 mmol/L ethanol in the presence or absence of 50 mumol/L TUDCA or UDCA. Cells were also pretreated with 80 mmol/L EtOH and then exposed to 50 mumol/L bile acids. Cytotoxicity was assessed by the metabolism of formazan (3-(4,5-dimethyl-thiazol-2-yl)-2, 5-diphenyl tetrazolium bromide and sodium 3,3'-(phenylamino) carbonyl-3,4-tetrazolium-bis (4-methoxy-6-nitro) benzene sulfonic acid hydrase and by the release into the culture medium of different enzymes (aspartate aminotransferase, glutamate dehydrogenase, gamma-glutamyl transferase, and lactate dehydrogenase).

RESULTS

The incubation of Hep G2 with EtOH significantly (P < 0.001) increased cytotoxicity. Both TUDCA or UDCA reduced cytoxicity to a similar extent (P < 0.001). Cells pretreated with EtOH and then added with TUDCA or UDCA responded differently because TUDCA was significantly more effective (P < 0.05) than an equimolar dose of UDCA in reversing the damage. Electron microscopic examination revealed that TUDCA and UDCA were both able to prevent mitochondrial damage and to reduce steatosis induced by EtOH.

CONCLUSIONS

Low doses of TUDCA and UDCA protect Hep G2 cells from EtOH-induced cytotoxicity. However, TUDCA seems to be more effective than UDCA in reversing the damage.

Prevalence of chronic liver disease in the general population of northern Italy: the Dionysos Study

Data on the prevalence of chronic liver disease, derived from selected series of hospitalized patients or from mortality registers, underestimate the prevalence of chronic liver disease. The Dionysos Study is a cohort study that investigated for the first time the prevalence of chronic liver disease in a general population. All the citizens of two towns in northern Italy, Campogalliano and Cormons, aged 12 to 65 yr were contacted by letter. From March 1991 through March 1993, 6,917 of a total of 10,150 citizens were enrolled (compliance, 69%). The standardized protocol for each enrollee included (a) a color-illustrated food questionnaire on dietary habits and alcohol intake; (b) a detailed medical history, including questions on risk factors for chronic liver disease; (c) a physical examination; and (d) blood tests for AST, ALT, gamma-glutamyltranspeptidase, mean cell volume, platelet count and hepatitis B virus and hepatitis C virus markers. Signs suggestive of chronic liver disease were seen in 21.3% of the subjects, and who then underwent further liver function tests, upper abdominal ultrasonography and, when necessary, liver biopsy. Persistent signs of chronic liver disease were present in 17.5% of the subjects, including 1.1% with cirrhosis and 0.07% with hepatocellular carcinoma. The prevalence rates of hepatitis B virus and hepatitis C virus positivity (second-generation enzyme-linked immunosorbent assay) were 1.3% and 3.2%, respectively. Alcohol abuse was the etiological agent in 23%.(ABSTRACT TRUNCATED AT 250 WORDS)

Ursodiol in the long-term treatment of chronic hepatitis: a double-blind multicenter clinical trial

Ursodeoxycholic acid (UDCA or ursodiol) administration has been associated with a reduction of serum liver enzymes in patients with chronic liver disease and with improvement of liver histology in patients with primary biliary cirrhosis. To establish the potential therapeutic efficacy of ursodiol in chronic hepatitis, serum biochemistry and liver histology were investigated in a multicenter, double-blind placebo controlled clinical trial. Sixty patients with non-cholestatic chronic active (mild or severe) hepatitis, mainly of viral (virus C) etiology and almost completely asymptomatic, were enrolled in 3 centers: 29 were assigned to receive placebo and 31 UDCA (600 mg/day) for 1 year. Demographic, biochemical, virological and histological features were balanced between the 2 groups at the entrance into the study. Fifty-six patients (34 males, 22 females; 19 with cirrhosis; 5 HBsAg-positive; 45 anti-HCV positive) were included in the final analysis. Compliance was checked by measuring UDCA levels at the 3 follow-up visits (3, 6 and 12 months). Liver biopsy was performed at the beginning and at the end of treatment and was evaluated blindly by our pathologist (F.C.). Alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gammaglutamyltransferase (GGT) levels were significantly reduced by 25% from baseline values during treatment with ursodiol but not with placebo. The efficacy of UDCA in lowering serum AST and ALT was more pronounced in the presence of cirrhosis. The semiquantitative liver histological score used remained substantially unchanged after treatment and no differences between placebo and UDCA were found for portal or periportal necrosis or inflammation, intralobular degeneration, cholestasis or fibrosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Transport of sulfobromophthalein and taurocholate in the HepG2 cell line in relation to the expression of membrane carrier proteins

The transport of two different classes of organic anions (cholephilic dyes; the sulfobromophthalein, BSP, and bile acids; taurocholate, TC) was investigated in the HepG2 cell line. At 37 degrees C, BSP uptake was found to be biphasic with an apparent saturative curve in the concentration range between 0-6 microM followed by a linear component up to 18 microM. Kinetic constant determination showed an apparent Km of 26.6 +/- 3.1 microM and a Vmax of 5.64 +/- 0.82 nmol BSP.min-1.mg prot-1. At 4 degrees C, uptake was linear. By subtracting this latter component from the total uptake, a saturable, carrier mediated uptake was found with an apparent Km of 3.6 +/- 1.0 microM BSP and a Vmax of 0.37 +/- 0.04 nmol BSP.min-1.mg prot-1 (m +/- SEM, n = 6). These values were fully comparable with those found in freshly isolated male hepatocyte. Immunoblot analysis of HepG2 cell plasma membrane revealed the presence of bilitranslocase when tested against a monospecific antibody against this carrier molecule. On the contrary, TC uptake was linear up to concentration of 100 microM TC. No difference was observed in the presence or absence of Na+. Immunoprecipitation analysis showed the absence of the putative carrier of TC. These data indicate that the HepG2 cell line expresses a functioning bilitranslocase-mediated system. Conversely, carrier mediated bile acid uptake is absent in line with the lack of expression of the carrier protein.

Correlation between bromodeoxyuridine labelling and ornithine decarboxylase levels in normal rectal mucosa of patients with colorectal adenoma

We studied rectal cell proliferation by means of bromodeoxyuridine labelling and ornithine decarboxylase activity assay in 16 patients with colorectal adenoma. In each patient, three rectal biopsy specimens taken from normal-appearing mucosa were incubated with bromodeoxyuridine (BrdU), fixed in ethanol and stained with avidin-biotin peroxidase complex using a monoclonal antibody against BrdU. In addition, two biopsies were homogenized and incubated with [1-14C]-ornithine for ornithine decarboxylase (ODC) assay. A direct, significant correlation was found between BrdU-labelling index and ODC levels in the mucosa (r = 0.6511, P less than 0.01). We conclude that BrdU labelling and ODC activity assay give comparable results in the analysis of cell proliferation rate of rectal mucosa. These methods are useful to investigate rectal cell proliferation pattern of patients with increased risk of colorectal cancer.

A simple score for the identification of patients at high risk of organic diseases of the colon in the family doctor consulting room. The Local IBS Study Group

In order to develop a scoring system for selecting patients at high risk of organic diseases of the colon, who would need a colonoscopy or a barium enema, we conducted a study with 14 GPs in the local health care district of Modena. Over one year, 254 consecutive patients who consulted their GP for chronic abdominal pain were asked to answer a guided questionnaire. A checklist of simple parameters suggestive of the presence of organic diseases of the colon was also registered by the GP. For the final diagnosis, the patients underwent either a colonoscopy or a barium enema. Data collected were analysed by means of a stepwise logistic regression analysis to obtain a weighted score for the diagnosis of either irritable bowel syndrome (score less than 0) or organic disease (score greater than 0). Out of the 25 parameters explored, six were significantly more common among patients with organic disease and weighted as positive score (namely ESR greater than 17 mm, first hour, history of blood in the stool, leukocytosis greater than 10,000 cm3, age greater than 45 years, slight fever and presence of neoplastic colonic diseases in first-degree relatives). On the contrary, five parameters were more frequent among patients with irritable bowel syndrome and weighted as negative score (namely visible distension of the abdomen, feeling of distension, presence of irritable bowel syndrome in first degree relatives, flatulence and irregularities of bowel movement). Our scoring system correctly classified 83.5% of the cases, and it was very sensitive (82.4%) for the diagnosis of organic disease.(ABSTRACT TRUNCATED AT 250 WORDS)

The role of calcium precipitation in the sulfoglycolithocholate-induced cholestasis of the bile fistula hamster

Sulfate glycolithocholic acid (SGLC) has been shown to be highly cholestatic in the rat. This study was performed in order to gain understanding of the mechanisms of SGLC-induced cholestasis and the aim of the investigation was to explore the hypothesis that SGLC could cause a precipitation of calcium in bile. We studied the effects of intravenously administrated SGLC on bile flow, biliary lipids secretion and calcium excretion in the female bile fistula hamster. We also performed in-vitro studies with a Ca2(+)-selective electrode in order to measure the calcium binding capacity of SGLC. The results showed that after 1 h of infusion of 8 mumol/100 g body weight [14C]SGLC bile flow dropped to zero. During the infusion period a fine white sludge was visible in the test tube used for bile collection. TLC and HPLC analysis of both the supernatant and the precipitate showed that unchanged SGLC was excreted into bile. Up to 20% of biliary SGLC and more than 50% of the total Ca2+ present in bile was precipitated. The SGLC/Ca2+ molar ratio in the precipitate was 1.12 +/- 0.3 (mean +/- S.D. of four experiments). Light and electron microscopy of the liver did not show any specific abnormalities. The Ca2+ binding activity of SGLC in vitro, was highest among the bile acids tested at a concentration of 0.1 mM, when almost 100% of bile acids are in the monomeric (non-micellar) form. This suggests that among the bile acids, SGLC exerts the strongest binding activity on free calcium ions.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of etofibrate on cholesterol and bile acid metabolism in the hamster

Hamsters were given etofibrate at a dose of 300 mg/kg body wt, by gavage for 5 days, while being fed a chow diet. After treatment, serum cholesterol levels were 27% lower compared to those of the control animals. A similar trend was observed for triglyceride levels. Hepatic lipid levels were unchanged by the treatment. HMG-CoA reductase and acylCoA cholesterol acyltransferase were decreased while cholesterol 7 alpha-hydroxylase was not significantly modified by etofibrate. A choleretic effect and an increase of cholesterol excretion into hepatic bile was observed in treated animals. Nevertheless, composition and cholesterol saturation index of gallbladder bile were similar in control and treated animals. With respect to controls, hepatic bile of treated hamsters contained a lesser amount of cholic and deoxycholic acid and a greater amount of ursodeoxycholic acid.

Effect of ursodeoxycholic acid treatment on alanine aminotransferase and gamma-glutamyltranspeptidase serum levels in patients with hypertransaminasemia. Results from a double-blind controlled trial

The ability of ursodeoxycholic acid (UDCA, 600 mg/day) to lower alanine aminotransferase (ALT) blood levels in blood donors rejected for donation because of fluctuating hypertransaminasemia was evaluated in a randomized, controlled, double-blind clinical trial vs. placebo. All subjects with ALT values at least twice the normal upper limit in at least two out of three previous checks (the last one not more than 1 month previously) were admitted to the study. Checks were carried out 1, 2 and 3 months after the admission. 59 out of 65 patients completed the study. Although all patients were asked to abstain from alcohol, more than 50% of them in both groups had basal gamma-glutamyltransferase (gamma-GT) values higher than normal. After 1 month of treatment and throughout its duration, UDCA was effective in lowering ALT in all patients (30% decrease with respect to the basal value) and, especially, in lowering gamma-GT in those patients with elevated levels (50% decrease with respect to the basal value). This decrease was significantly different from the spontaneous 10% decrease of the ALT and gamma-GT levels observed in the placebo group. 3 months after suspension of therapy a rebound of both ALT and gamma-GT to values comparable to the basal ones or even higher was found only in UDCA-treated patients. We conclude that the short-term administration of UDCA is free of hepatotoxic effects and could be useful in lowering ALT and gamma-GT serum levels. The real significance of UDCA treatment in the natural history of chronic liver diseases deserves further investigation.

Ethanol-induced increase in cytosolic estrogen receptors in human male liver: a possible explanation for biochemical feminization in chronic liver disease due to alcohol

The hepatic cytosolic estrogen receptor content was measured in liver samples from patients with normal livers and from patients with nonalcoholic cirrhosis, alcoholic cirrhosis and alcoholic hepatitis. The estrogen receptor content of normal liver was 5.2 +/- 3.5 fmoles per mg of cytosolic protein. Levels which were not significantly different from this were found in the samples from patients with nonalcoholic cirrhosis (2.1 +/- 2.0 fmoles per mg of cytosolic protein). The cytosolic estrogen receptor content in the livers of patients with alcoholic cirrhosis who were abstaining was 4.2 +/- 3.6 fmoles per mg of cytosolic protein, but it increased to 10.4 +/- 4.9 fmoles per mg of protein in the livers of patients with alcoholic cirrhosis who were drinking, to 17.3 +/- 8.7 fmoles per mg of protein in the livers of patients with alcoholic hepatitis with cirrhosis and to 22.7 +/- 15.7 fmoles per mg of protein in the livers of patients with alcoholic hepatitis without cirrhosis. Alcohol abuse appeared, therefore, to induce an increase in the estrogen receptor content of human liver, especially in patients who were drinking and had histological evidence of acute liver damage (alcoholic hepatitis). The increase in hepatic estrogen receptor which we have observed may be involved in the molecular mechanisms underlying the feminization of the liver in alcoholic males.

Sex steroid modulation of the hepatic uptake of organic anions in rat

To investigate the role of sex steroids in the sex-related difference in the hepatic uptake of organic anions, sulphobromophthalein (bromsulphalein, BSP) transport was measured in hepatocytes isolated from rats either deprived of hormonal influence by castration at prepubertal age or after hormonal substitution. In control animals, the kinetics of BSP uptake showed the presence of two components: one saturable (0-3 microM), with high affinity and low capacity, and the other linear (9-30 microM), probably related to the non-specific component of BSP uptake. Sex difference was detected only in the saturable portion of the uptake process as the apparent Km was significantly lower in females than in males (3.8 +/- 0.7 vs. 6.1 +/- 1.8 microM, mean +/- S.D. of six animals, P less than 0.01). In contrast, no difference was observed in Vmax (2.3 +/- 0.3 vs. 2.2 +/- 0.7 nmol BSP.(mg protein)-1.min-1). Castration was associated with the disappearance of the saturable uptake site and abolished the sex difference. Progesterone treatment of castrated males failed to restore the saturable kinetics of BSP uptake. In contrast, administration of oestradiol to castrated males or testosterone to castrated females did restore the saturable kinetics of the high-affinity BSP uptake. Km and Vmax were comparable to those of adult females and males, respectively, with the exception of testosterone which induced a Vmax value higher than that observed in the other groups of animals. These data suggest that the influence of oestrogen and testosterone is necessary for the expression of the high-affinity, low-capacity carrier-mediated process of hepatic BSP uptake.(ABSTRACT TRUNCATED AT 250 WORDS)

Taurine increases bile acid pool size and reduces bile saturation index in the hamster

There is evidence that increased availability of taurine enhances the proportion of taurine-conjugated bile acids in bile. To explore the possibility that taurine treatment could also influence hepatic cholesterol and bile acid metabolism, we fed female hamsters for 1 week and measured both the biliary lipid content and the microsomal level of the rate-limiting enzymes of cholesterol and bile acid synthesis. In these animals the cholesterol 7 alpha-hydroxylase activity was significantly greater in respect to controls (P less than 0.05). The total HMG-CoA reductase activity, as well as that of the active form, was similarly increased. The stimulation of 7 alpha-hydroxycholesterol synthesis was associated with an expansion of the bile acid pool size in taurine-fed animals. Taurine feeding was observed to induce an increase in bile flow as well as in the rate of excretion of bile acids, whereas the secretion rate of cholesterol in bile was decreased. As a consequence, the saturation index was significantly lower in taurine-fed animals (P less than 0.05). The possible mechanisms through which taurine exhibits the modification of the enzyme activities and of the biliary lipid composition are discussed.

Effect of tauroursodeoxycholate feeding, with or without taurine supplementation on hepatic bile acids and cholesterol metabolism in the hamster

This study reports the effect of short-term tauroursodeoxycholic acid (TUDCA) and of TUDCA with addition of taurine on the lipid composition of gallbladder bile, on cholesterol and bile acid synthesis and intestinal excretion, in the female hamsters. After either one or two weeks, the percentage of ursodeoxycholic acid (UDCA) and chenodeoxycholic acid (CDCA) in bile of treated hamsters significantly increased. Both treatments (TUDCA alone or TUDCA + taurine) decreased the percentage of cholic acid without affecting 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase or cholesterol 7 alpha-hydroxylase activities. Sterol and bile acid content of the feces collected during the period of the study did not show any difference. Bile acid glycine to taurine conjugation ratio (G/T ratio) in TUDCA treated animals was significantly higher in respect to controls after only one week of treatment. On the contrary, bile acid G/T ratio significantly decreased in the group of animals supplemented with taurine, but only after two weeks of treatment.

Bile acid inhibition of taurocholate uptake by rat hepatocytes: role of OH groups

To define further the structural specificity of the taurocholate uptake site, we studied the ability of a variety of taurine-conjugated bile acids with differing hydroxyl substituents on the sterol moiety to inhibit [14C]taurocholate uptake. Rat hepatocytes isolated by collagenase perfusion were incubated in a tris(hydroxymethyl)aminomethane-phosphate buffer containing [14C]taurocholate (2.5-100 microM) in the presence or absence of inhibitor bile acid. Stronger inhibitors were studied at a fixed concentration of 5 microM, weaker ones at 25 microM. Initial uptake velocity was measured by sedimenting an aliquot of cells through silicone oil into 3 N KOH every 15 s for 1 min. Uptake velocity (nmol X mg protein-1 X min-1) could then be related to taurocholate concentration and a Vmax and Km could be determined by applying a nonlinear least squares fit to the data obtained with or without inhibitor. The kinetic parameters allowed the determination of the type of inhibition and of inhibition constants (Ki) of the various test bile acids. The data indicate that bile acids containing a 6- or 7-OH group exhibit competitive inhibition, whereas bile acids with no 6- or 7-OH group exhibit noncompetitive inhibition. Of the compounds exhibiting competitive inhibition, Ki varied with the number of hydroxyl groups on the sterol moiety. We conclude that the presence or absence of a 6- or 7-OH group dictates the mechanism of inhibition; the number of hydroxyl substituents determines the potency of competitive inhibition.

Sex differences in the hepatic uptake of sulphobromophthalein in the rat

Sex difference in the hepatic uptake of sulphobromophthalein (BSP) was investigated in male and female rats in three different experimental models. In the intact animal the BSP plasma disappearance rate was significantly higher (P less than 0.01) in females than in males when 0.15 or 1.5 mumol/kg body wt. was injected. Comparable values were found at the highest BSP dose (15 mumol/kg body wt.) used. In the perfused liver, the first-pass hepatic extraction and the uptake velocity were significantly higher (P less than 0.001) in female rats at low BSP doses (0.3-750 mumol/g of liver) whereas identical values were found at higher concentrations. In hepatocytes isolated by collagenase perfusion, the BSP uptake occurs via two different uptake sites in both sexes. The Km of the high affinity sites was lower in females than in males (3.67 +/- 0.58 vs 7.24 +/- 0.68 mumol/l, P less than 0.001) whereas Vmax. showed comparable values (2.70 +/- 0.36 vs 2.47 +/- 0.45 nmol of BSP/mg of protein, NS). In contrast, no difference was found in the kinetic parameters of the low affinity sites (Km 50.6 +/- 31.1 vs 61.0 +/- 17.5 mumol/l; Vmax. 21.9 +/- 13.2 vs 25.0 +/- 3.6 nmol of BSP/mg of protein, mean +/- SD, NS, females and males respectively). Taken together these data show that low doses of BSP are taken up by the liver more efficiently in female than in male rats and are consistent with a sex-related difference in the affinity but not in the number of the BSP high affinity uptake sites.

Mechanisms of liver adaptation to prolonged selective biliary obstruction (SBO) in the rat

To determine changes which occur in selective biliary obstruction (SBO), we studied male adult Fischer rats after one month of either SBO or selective biliary cannulation (SBC) of the median lobe duct (MLD). In rats with SBC the ML was obstructed with a sealed PE-10 catheter placed in the MLD. One month later at laparotomy the ML was either drained or not drained for 30 min before the injection of 200 microCi [99Tc]DIDA (2,6-diethylacetoanilido-imino-diacetic acid). Bile was collected and biopsies of the obstructed ML and non-obstructed right lobe (RL) were taken at 1, 3, 10 and 30 min. Serum bile acid concentrations were higher in SBC not drained rats than in control as were hepatic bile acid concentrations. The latter, however, did not achieve statistical significance. In SBC-drained rats biliary bile acid secretion from the obstructed lobe was lower than that from the non-obstructed lobe for 30 min after the release of obstruction but was thereafter the same. Hepatic DIDA levels in both the obstructed and non-obstructed portions of liver from SBO animals were higher than in liver from controls, despite normal DIDA biliary excretion. This is in part explained by increased cytosolic binding of DIDA. In rats with SBO the MLD was simply ligated and transected. After one month uptake kinetics of [14C]taurocholate in freshly isolated hepatocytes from obstructed and non-obstructed lobes were similar suggesting that no major impairment of BA uptake occurs. We conclude that cholestasis is still present after 30 days of SBO in spite of the presence of interlobular biliary connections. The observed increased hepatic storage capacity for DIDA is probably an adaptive mechanism in mild chronic cholestasis.

BT-Paba test in the diagnosis of pancreatic exocrine insufficiency in cystic fibrosis: urinary and serum determinations compared

Urinary recovery and serum determination of Paba were carried out in 48 control children (C) and 53 paediatric patients with cystic fibrosis (CF) divided into three classes by age. Ninety and 120 min after the ingestion of 15 mg/kg of BT-Paba and of a standard meal, serum Paba was determined. In the same subjects the percentage Paba recovery was measured in the urine collected during an 8 h period after the same administration of BT-Paba. Correlation between urinary and serum Paba values was higher in the older children in respect to the 0-2-year-old infants. A urinary Paba test was less sensitive and specific than a serum Paba test in the evaluation of exocrine pancreatic function. The best discrimination between C and children with CF, using the maximal value of serum Paba at 90 or 120 min (peak), was obtained in the younger infants (0-2 years old). BT-Paba test with serum Paba peak determination is recommended as a substitute for the classical urinary Paba test in the evaluation of exocrine pancreatic function in paediatric patients, especially in the younger infants.