Novel controlled attenuation parameter for noninvasive assessment of steatosis using Fibroscan(®): validation in chronic hepatitis C.

A novel controlled attenuation parameter (CAP) has been developed for Fibroscan(®) to assess liver steatosis, simultaneously with liver stiffness measurement (LSM). We assessed CAP diagnostic accuracy in a large cohort of patients with chronic hepatitis C (CHC) virus. A total of 615 patients with CHC, who underwent both Fibroscan(®) and liver biopsy, were analysed. Fibrosis was graded using METAVIR score. Steatosis was categorized by visual assessment as S(0) : steatosis in <10% of hepatocytes, S(1) : 11-33%, S(2) : 34-66% and S(3) : 67-100%. Performances of CAP and liver stiffness were determined using receiver operating characteristic (ROC) curve analysis and cross-validated using the bootstrap method. The Obuchowski measure was used to assess overall accuracy of CAP and to differentiate between steatosis grades. In multivariate analysis, CAP was related to steatosis (P < 10(-15) ) independently of fibrosis stage (which was related to LSM). The areas under ROC curves using CAP to detect steatosis were 0.80 (95% CI, 0.75-0.84) for S ≥ S(1) , 0.86 (0.81-0.92) for S ≥ S(2) and 0.88 (0.73-1) S = S(3) . CAP exhibited a good ability to differentiate steatosis grades (Obuchowski measure = 0.92). Performance of LSM for fibrosis assessment confirmed results from previous studies. CAP is a novel tool to assess the degree of steatosis and both fibrosis and steatosis can be evaluated noninvasively during the same procedure using Fibroscan(®) , in patients with CHC.

Differentiating between benign and non-benign obesity: look at the liver.

Several recent experimental and epidemiological studies suggest that some forms of obesity may be benign and do not carry high risk of development of diabesity related disorders. This commentary discusses the available data supporting this concept, as well as the pathophysiological mechanisms.

The cholangiographic features of severe forms of ABCB4/MDR3 deficiency-associated cholangiopathy in adults.

We previously reported the association of ABCB4/MDR3 gene variants with a peculiar form of cholelithiasis in European adults, currently referred to as the LPAC syndrome. ABCB4/MDR3 deficiency is also now thought to be related to some forms of hepatolithiasis in Japan. We herein report in eight patients a new phenotype associated with ABCB4 gene mutations, characterized by a typical LPAC symptomatic disease associated with large uni- or multifocal spindle-shaped dilations of the intrahepatic bile ducts without any bile duct stenosis, and filled of gallstones. We excluded from this series, the patients with minimal intrahepatic bile duct dilations, with bile duct stenosis, with focal or diffuse irregular bile ducts compatible with the diagnosis of sclerosing cholangitis, with bile duct dilations that did not contain stones or alternatively with stones in bile ducts without large dilations. The prevalence of this phenotype does not exceed 5 to 10% of the patients with LPAC syndrome. Importantly, the ABCB4/MDR3 mutations observed in this series did not differ from those observed in patients with LPAC syndrome with no or minimal intrahepatic bile duct dilations that could suggest a specific genetic background in this setting. This variant shows similar sensitivity to ursodeoxycholic acid and may be partly reversible under long-term therapy. In summary, we describe here a peculiar cholangiographic phenotype of the LPAC syndrome characterized by single-shaped large bile duct dilations filled with cholesterol or brown-pigment stones. This phenotype is not associated with a peculiar type of ABCB4 mutation.

Ursodeoxycholic acid and chemoprevention of colorectal cancer.

Colorectal cancer is respectively the third and second most common cancer among men and women in France. Interest in chemoprevention for colorectal cancer has increased over the last two decades. Beside non-steroidal anti-inflammatory drugs, ursodeoxycholic acid (UDCA) may have chemopreventive action in colorectal cancer with a likely better tolerance. In high-risk populations such as patients with inflammatory bowel disease or prior colorectal adenoma or carcinoma, retrospective and prospective studies have suggested a beneficial effect of UDCA. In azoxymethane model, UDCA inhibits tumor development by countering the tumor-promoting effects of secondary bile acids, such as deoxycholic acid (DCA). The opposing effects of UDCA and DCA on lipid raft composition may be central to their effects on colonic tumorigenesis. Differential effects of DCA and UDCA on growth factor and inflammatory signals involved in colorectal carcinogenesis, such as epidermal growth factor receptors (EGFR) signaling and Cox-2 expression, likely mediate their opposing effects on colonic tumor promotion and tumor inhibition, respectively.

Triple therapy with ursodeoxycholic acid, budesonide and mycophenolate mofetil in patients with features of severe primary biliary cirrhosis not responding to ursodeoxycholic acid alone.

BACKGROUND/AIMS: To assess the benefit of the UDCA-budesonide combination in association with mycophenolate mofetil (MMF) in patients with primary biliary cirrhosis (PBC) at high risk of developing cirrhosis or liver failure. METHODS: Inclusion criteria for this three-year open study were: 1) suboptimal biochemical response to one-year UDCA therapy at 13-15 mg/kg/d; 2) significant interface hepatitis without cirrhosis at liver biopsy. Treatment regimen included UDCA (13-15 mg/kg/d), budesonide (6 mg/d) and MMF (1.5 g/d). All patients underwent a control biopsy at three years. RESULTS: Fifteen patients fulfilled the inclusion criteria. Six patients (41%) normalized biochemistries and seven (47%) had a partial but significant biochemical response, as defined by a serum bilirubin less than 17 micromol/L, alanine aminotransferase less than 70 UI/L and alkaline phosphatase less than 250 UI/L. Histological activity and fibrosis were markedly improved. Side effects were minimal or absent. CONCLUSIONS: Triple therapy with UDCA, budesonide and MMF may provide benefit in non-cirrhotic PBC patients with features of severe disease not responding to UDCA.

[Cholestasis and cholestatic liver diseases]. / Cholestase et maladies cholestatiques.

The main determinant of bile formation is an osmotic filtration process resulting from active transport of bile acids and other osmotic solutes (glutathion). Most of the membrane transporters ensuring bile formation have now been identified. The expression of these membrane transporters is regulated through transcriptional and post-traductional mechanisms. Transcriptional regulation is under the control of nuclear receptors activated by ligands such as bile acids, which act as endogenous steroids synthesized from cholesterol in hepatocytes. Cholestatic liver diseases comprise genetic diseases resulting from the complex interaction between genetic and environmental factors. Monogenic cholestatic diseases recently identified illustrate the key role of membrane transporters in biliary function. Bile acids and inflammatory mediators are potent modulators of transporters and nuclear receptor genes and thus trigger an adaptative response to cholestasis. The extent of this adaptative response could explain the compelling phenotypic variability of cholestatic diseases in childhood and adults. The first-line medical treatment is currently ursodeoxycholic acid and in case of failure of this medical treatment, liver transplantation is required. Recent progress in the molecular pathogenesis of bile formation and cholestatic liver diseases is expected to provide the design of drugs targeted to the molecular abnormalities typical of cholestatic diseases.

Phenotypic expression of ferroportin disease in a family with the N144H mutation.

Ferroportin is a putative transmembrane channel involved in the exit of iron out of the enterocytes, the macrophages and the hepatocytes. Mutations in the human gene coding ferroportin have been linked to an unusual form of iron overload, now referred to as "hemochromatosis type IV" or "ferroportin disease" characterized by a prevalent iron overload of macrophages and liver Küpffer cells. We report four patients from a same family with ferroportin disease associated with the N144H mutation. We show that in this family the mutation which is fully penetrant, may act through an increased iron export from macrophages as suggested by the unexpected absence of iron overload in the spleen and bone marrow detected by magnetic resonance imaging, that it co-segregates with a phenotype close to the classical form of HFE-associated hemochromatosis and was associated, in the oldest patient, with the development of hepatocellular carcinoma in a non cirrhotic liver. Our findings illustrate the existence of a genotype-phenotype relationship in "ferroportin disease", suggest that MRI may be useful in determining this phenotype and show that hepatocellular carcinoma may occur in these patients even without cirrhosis. This observation justifies careful follow-up of this subgroup of patients.

Endothelin-1 is synthesized and inhibits cyclic adenosine monophosphate- dependent anion secretion by an autocrine/paracrine mechanism in gallbladder epithelial cells.

Ion and fluid transport across the biliary epithelium contributes to bile secretion. Since endothelin (ET)-1 affects ion transport activities and is released by human gallbladder- derived biliary epithelial cells in primary culture, we examined the expression of ET peptides and ET receptors and the influence of ET-1 on ion transport in this epithelium ex vivo. In freshly isolated gallbladder epithelial cells, preproET-1, -2, and -3 mRNAs were detected by reverse transcription PCR and ET-1 isopeptide was identified by chromatography. The cells also displayed ET receptor mRNAs and high-affinity binding sites for ET-1, mostly of the ETB type. Electrogenic anion secretion across intact gallbladder mucosa was stimulated by forskolin, secretin, and exogenous ATP, as assessed by short-circuit current (Isc) increases in Ussing-type chambers. ET-1 inhibited forskolin- and secretin-induced changes in Isc, without affecting baseline Isc or ATP-induced changes. Accordingly, ET-1 significantly reduced the accumulation of intracellular cAMP elicited by forskolin and secretin in the epithelial cells, and this effect was abolished by pertussis toxin. This is the first evidence that ET-1 is synthesized and inhibits, via a Gi protein-coupled receptor, cAMP-dependent anion secretion in human gallbladder epithelium, indicating a role in the control of bile secretion by an autocrine/paracrine mechanism.

Elastography in hepatology.

A common characteristic of all chronic liver diseases is the occurrence and progression of fibrosis toward cirrhosis. Consequently, liver fibrosis assessment plays an important role in hepatology. Besides its importance for prognosis, determining the level of fibrosis reveals the natural history of the disease and the risk factors associated with its progression, to guide the antifibrotic action of different treatments. Currently, in clinical practice, there are three available methods for the evaluation of liver fibrosis: liver biopsy, which is still considered to be the 'gold standard'; serological markers of fibrosis and their mathematical combination - suggested in recent years to be an alternative to liver biopsy - and, more recently, transient elastography (TE). TE is a new, simple and noninvasive method used to measure liver stiffness. This technique is based on the progressing speed of an elastic shear wave within the liver. Currently, there are only a few studies that have evaluated TE effectiveness in chronic liver diseases, mostly in patients infected with the hepatitis C virus. Further studies are needed in patients with chronic liver disease, to assess the effectiveness of the fibrosis treatment.

Ursodeoxycholic acid therapy of chronic cholestatic conditions in adults and children.

Cholestasis can be defined as the manifestation of defective bile acid transport from the liver to the intestine. Most chronic cholestatic conditions can progress towards cirrhosis. At this stage, liver transplantation is the treatment of choice. Most of the drugs so far evaluated show some degree of efficacy but have major side effects. Given that ursodeoxycholic acid (UDCA) has no apparent toxicity in humans, it was postulated that long-term treatment with this drug might displace endogenous bile acids and thus reverse their suspected toxicity. We demonstrated that long-term UDCA therapy slows the progression of primary biliary cirrhosis and reduces the need for liver transplantation. In this review, we give the rationale for the use of UDCA in cholestasis and discuss its possible mechanisms of action. We also give an overview of current data on UDCA therapy of chronic cholestatic disorders in adults and children.

Impact of early-untreated HIV infection on chronic hepatitis C in intravenous drug users: a case-control study.

OBJECTIVE: The impact of early-untreated HIV infection on chronic hepatitis C was determined in a case-control study, aimed at limiting factors associated with the progression of immunodeficiency. METHODS: HIV-infected patients attending for a medical examination during 1995-1996 were systematically screened for: previous intravenous drug use without other HIV or Hepatitis C virus (HCV) risk factor, CD4 cell count > 200/microl, no AIDS, no antiretroviral treatment, positive anti-HCV antibody, negative hepatitis B surface antigen, abnormal aminotransferase activity. Thirty-eight consecutive eligible HIV-infected patients (cases) were included. Thirty-eight HCV-infected patients without HIV infection whose unique risk factor was intravenous drug use (controls) were paired to cases according to age, sex, and duration of HCV infection. RESULTS: Cases and controls had similar ages, sex ratios, duration of HCV infection, and alcohol intake. They were infected predominantly by genotypes 1 and 3. Viraemia was higher in cases than in controls. METAVIR histological scores of activity and fibrosis in cases versus controls were 2.2 +/- 0.8 versus 1.6 +/- 0.7 (P = 0.0008) and 1.8 +/- 1 versus 1.5 +/- 0.8 (P = 0.06), respectively. The percentage of cirrhosis was higher in cases, without reaching statistical difference. The progression rate of fibrosis was higher in cases. Age at contamination and METAVIR activity score were significantly associated with the progression of fibrosis in cases. CONCLUSION: Early-untreated HIV infection is associated with higher HCV viraemia and more severe liver injury in intravenous drug users with chronic hepatitis C.

Effect of protein binding on testosterone extraction by human cirrhotic liver: evidence for a dissociation-limited uptake.

Testosterone (T) is a protein-bound substance, the hepatic extraction of which largely exceeds the free plasma fraction. In this study we attempted to determine if the dissociation of T from plasma proteins is the limiting factor for testosterone hepatic uptake in patients with cirrhosis. For this purpose we measured the hepatic uptake of T and the peripheral plasma concentrations of the different fractions of the hormone (total, free, albumin-bound, and sex hormone-binding globulin (SHBG)-bound) in 12 men with alcoholic cirrhosis. The hepatic extraction of T (mean = 42%) greatly exceeded the non-SHBG-bound fraction of T (free T plus albumin-bound T: mean = 13%). Thus, a substantial amount of SHBG-bound T must have entered the liver. A theoretical extraction ratio was calculated based upon the dissociation rate constants of T from albumin and SHBG and upon an estimate of sinusoidal transit time of plasma through the liver. The similarity between the measured and expected values indicates that the limiting step in hepatic uptake of T might be SHBG binding.

Pharmacokinetics of intravenous and oral pentoxifylline in healthy volunteers and in cirrhotic patients.

The pharmacokinetics of pentoxifylline were investigated in six healthy volunteers and in 10 patients with alcoholic cirrhosis. After a 100 mg intravenous infusion, pentoxifylline elimination half-life was prolonged in cirrhotic patients (2.12 +/- 1.22 hours versus 0.83 +/- 0.29 hours, p less than 0.05) because of a decrease in its plasma clearance (1.44 +/- 0.46 L.hr-1.kg-1 in patients with cirrhosis versus 3.62 +/- 0.75 L.hr-1.kg-1 in volunteers, p less than 0.001). The elimination half-life of the metabolite (5-hydroxypentoxifylline) was similar to that of the parent compound. After oral administration of a 400 mg sustained-released tablet, absolute bioavailability of pentoxifylline increased in cirrhotic patients (0.71 +/- 0.24 versus 0.33 +/- 0.13, p less than 0.01). Although plasma concentrations of pentoxifylline and hydroxypentoxifylline were significantly increased in cirrhotic patients, the AUCpentoxifylline/AUChydroxypentoxifylline ratio remained unchanged in both groups after either intravenous or oral administration. These findings show that liver cirrhosis profoundly alters the pharmacokinetics of pentoxifylline. However the formation of hydroxypentoxifylline is not modified in these patients, suggesting an extrahepatic metabolism.

Ursodeoxycholic acid (UDCA) in the treatment of chronic cholestatic diseases.

Several studies suggest that UDCA treatment has beneficial effects in chronic cholestatic diseases. We designed a controlled trial to assess the efficacy and tolerance of UCDA in primary biliary cirrhosis (PBC): 73 patients received UDCA (13-15 mg/kg per day) and 73 a placebo. One side-effect required interruption of therapy in each group. The relative risk of treatment failure (doubling of the bilirubin level or occurrence of a severe complication of cirrhosis) was 3 times higher in the placebo group. Pruritus resolved in 40% of the patients of UDCA group vs 19% in placebo group. Biological and histological parameters significantly improved in the patients receiving UDCA. Unexpectedly, immune parameters, including IgM levels and anti-mitochondrial antibody titers, also improved. The Mayo risk score was significantly different between the two groups at one and two years, suggesting that UDCA could prolong survival in PBC. Recent studies suggest that UDCA could have immunoregulating properties. Abnormal MHC class I expression by hepatocytes, observed in PBC, was dramatically reduced by UDCA treatment. Cholestasis itself induces hepatic MHC expression: hepatocyte MHC class I expression was present in 6/6 cholestatic patients vs 0/8 control subjects. Experimental cholestasis in the rat induced MHC class I expression. Cyclosporin or corticosteroids had no effect on this overexpression, suggesting that an immune mechanism is not involved in this phenomenon. To assess the effect of bile acids on MHC expression, human hepatocytes were incubated with bile acids. Chenodeoxycholic acid (CDCA) (an endogenous bile acid) but not UDCA induced a dose-dependent MHC class I hyperexpression. UDCA suppressed the CDCA-induced MHC hyperexpression.(ABSTRACT TRUNCATED AT 250 WORDS)

Properties of Na+, K+-ATPase of liver plasma membranes in the hamster.

This study was designed to establish the properties of liver plasma membranes (LPM) Na+,K+-ATPase in the hamster and to determine whether a similar assay may be used to measure enzyme activity in the hamster and in the rat. Maximal Na+,K+-ATPase activity was obtained when the assay medium contained 5 mM Mg APT2- with or without 1 mM free Mg2+, 120 mM Na+, 12,5 mM K+. The incubation must be performed at 37 degrees C, pH 7.4. In the absence of free Mg2+, the saturation curve with respect to the substrate Mg ATP2- resulted in biphasic complex kinetics with a maximal activity at a substrate concentration of 5 mM. In the presence of 1 mM free Mg2+ activation of Na+,K+-ATPase and modification of the kinetics were observed: the biphasic curve tended to disappear and to become of the Michaelis-Menten type. The apparent Km for Mg APT2- was 0.36 mM and the Vmax 34.5 mumol.h-1.mg protein-1. In the presence of 10 mM free Mg2+ a decrease in the Vmax was observed without any effect on the apparent Km for Mg APT2-. It is concluded that the same incubation medium may be used to assay LPM N+,K+-ATPase from hamster and rat and that the addition of 1 mM free Mg2+ to the incubation medium is recommended to obtain Michaelis-Menten kinetics in order to eliminate complex kinetics due to the absence of free Mg2+.

HBV genotypic resistance to lamivudine in kidney recipients and hemodialyzed patients.

BACKGROUND: Lamivudine is a potent inhibitor of human immunodeficiency virus reverse transcriptase and hepatitis B virus (HBV) DNA polymerase. Its overall efficiency is clearly hampered by relapse at discontinuation and by risk of genotypic resistance. We describe herein the first cases of HBV resistance to lamivudine in kidney recipients and hemodialyzed patients. METHODS: We analyzed 26 HBV-infected kidney recipients and five hemodialyzed patients treated with lamivudine who became serum HBV DNA-negative (by Digene test). The biological and virological follow-up identified breakthrough as defined by the reappearance of serum HBV DNA. In two cases of breakthrough, HBV DNA was amplified and sequenced through the polymerase domain, including the YMDD motif, before the beginning of treatment and at time of breakthrough to determine genotypic mutations. RESULTS: Ten breakthroughs (reappearance of serum HBV DNA) were observed after a median follow-up of 11 months in eight kidney recipients and two hemodialyzed patients after a median duration of treatment of 16.5 (from 4 to 31) months of treatment. Previous HBe/anti-HBe seroconversion was not observed in the patients who escaped. In two kidney recipients, the comparison of HBV-DNA sequences before the treatment and after the breakthrough identified in one case a mutation of the highly conserved YMDD motif (YVDD), whereas in the second case, no genotypic mutation was observed in the sequenced region. CONCLUSION: We report the first cases of HBV genotypic resistance to lamivudine in kidney recipients and hemodialysis patients. Genotypic resistance is observed after 4-31 months of therapy. The YMDD mutation does not account for all cases of virological escape.

A randomised controlled study of propranolol for prevention of recurrent gastrointestinal bleeding in patients with cirrhosis.

74 cirrhotic patients with a history of variceal or gastric bleeding were randomly assigned to treatment with propranolol (40 to 360 mg/day) or placebo. The patients were all in good condition and doses of propranolol were titrated until a 25% reduction in heart rate was achieved. After 2 years, the cumulative percentage of patients free from rebleeding was significantly greater among the patients receiving propranolol (79%) than in the placebo group (32%; p less than 0.0001). Similarly, the percentage of surviving patients was significantly greater with propranolol (90%) than with placebo (57%; p less than 0.02) after 2 years. It was concluded that in cirrhotic patients in good condition, propranolol reduced both the risk of recurrent gastrointestinal haemorrhage and the mortality rate during a 2-year period of continuous administration of the drug.

Hepatic transport of bile acids in the isolated perfused rat liver. Structure-kinetic relationship.

We studied the transport kinetics of a series of bile acids from blood to bile in the isolated perfused rat liver in order to define better the relationship between chemical structure of bile acid molecules and efficiency of the overall hepatic transport process. BA studied were taurocholate (TC), glycocholate (GC), cholate (C), tauroursodeoxycholate (TUDC), ursodeoxycholate (UDC) and hyodeoxycholate (HDC). Estimates of intrinsic hepatic clearance (Cl(int)), maximal secretory rate (Vmax) were provided from the analysis of the relationship between bile acid removal rates and sinusoidal concentration under steady-state conditions. TC and TUDC had the highest Cl(int) (about 5 ml/min/g liver) and Vmax (about 800 nmol/min/g liver) followed in order by GC (1.71 ml/min/g liver; 442 nmol/min/g liver); C (1.25 ml/min/g liver; 252 nmol/min/g liver); HDC (0.86 ml/min/g liver; 238 nmol/min/g liver); UDC (0.72 ml/min/g liver; 176 nmol/min/g liver). The findings suggest that the efficiency of the overall hepatic transport of bile acids is highly dependent on their molecular structure and that conjugation has a more important effect on both Cl(int) and Vmax that the number or position of hydroxyl groups.

Independent and combined actions of interleukin-1 beta, tumor necrosis factor alpha, and glucagon on amino acid metabolism in the isolated perfused rat liver.

Conflicting reports concerning the hepatic effects of interleukin-1 beta (IL-1 beta) and tumor necrosis factor alpha (TNF alpha) in the metabolic response to injury led us to investigate the influence of physiological concentrations of these cytokines on amino acid metabolism in the isolated perfused rat liver. IL-1 beta was ineffective at a concentration of 1 ng/mL, whereas TNF alpha (0.7 ng/mL) reduced the uptake of some of the main gluconeogenic amino acids (alanine, -55.3 +/- 4.9 v -72.9 +/- 13.7 nmol.min-1.g-1 in controls, P < .05) without affecting urea synthesis. TNF alpha increased glucose uptake by 237% and inhibited that of free fatty acids (-1.6 +/- 1.4 v -9.9 +/- 6.7 nmol.min-1.g-1 in controls, P < .05). IL-1 beta and TNF alpha potentiated glucagon-induced total amino acid uptake by 56% and 87%, respectively. They also affected glucagon-activated gluconeogenesis, leading to an initial potentiation of glucose release. Thereafter, IL-1 beta inhibited glucagon action, leading to an hepatic uptake of glucose. These results indicate that (1) in the conditions of the study, IL-1 beta has no direct effect on hepatic amino acid exchanges and utilization; (2) TNF alpha which exerted an inhibitory effect on these parameters, could be involved in the reduced amino acid exchanges during the end stage of sepsis; (3) the TNF alpha-induced increase in glucose uptake could be related to an inhibition of gluconeogenesis and/or to the activation of glucose utilization by Kupffer cells; (4) IL-1 beta and TNF alpha both potentiate the action of glucagon on hepatic amino acid uptake and utilization; and (5) complex interactions between Kupffer cells and hepatocytes on the one hand and between cytokines and hormones on the other hand could account for the differences in hepatic metabolism according to the stage of the response to injury.