After portal branch ligation in rat, nuclear factor kappaB, interleukin-6, signal transducers and activators of transcription 3, c-fos, c-myc, and c-jun are similarly induced in the ligated and nonligated lobes

Several studies have emphasized the involvement of transcription factors, cytokines, and proto-oncogenes in initiating the regenerative process after partial hepatectomy. To assess whether these events do specifically occur in a cellular system undergoing regeneration, we studied the induction of nuclear factor kappaB (NFkappaB), interleukin-6 (IL-6), signal transducers and activators of transcription 3 (Stat3), c-fos, c-myc, c-jun, after portal branch ligation (PBL), which produces atrophy of the deprived lobes (70% of the liver parenchyma), whereas the perfused lobes undergo compensatory regeneration. Nuclear extracts and total RNA were prepared from control livers as well as from atrophying and regenerating lobes at 0.5, 1, 2, 5, and 8 after PBL. NFkappaB and Stat3 induction were studied by electrophoretic mobility shift assays and Western blotting. IL-6 and proto-oncogenes expressions were assessed by reverse transcription polymerase chain reaction and Northern blotting, respectively. Assays were also performed after a sham operation. NFkappaB and Stat3 protein expression and DNA binding were rapidly and similarly induced in nuclear extracts from the atrophying and regenerating lobes. IL-6 was elevated in both lobes from 1 to 8 hours after PBL as well as c-fos, c-myc, and c-jun during the first 2 hours. IL-6 and Stat3 but not NFkappaB were also elevated after a sham operation. These findings suggest that the cellular and molecular changes occurring early in a regenerating liver are nonspecific, possibly stress-induced, cellular responses. They do not indicate the future evolution towards atrophy or regeneration.

Meloxicam-induced liver toxicity

We report the case of a female patient with rheumatoid arthritis who developed acute cytolytic hepatitis due to meloxicam. Recently introduced in Belgium, meloxicam is the first nonsteroidal antiinflammatory drug with selective action on the inducible form of cyclooxygenase 2. The acute cytolytic hepatitis occurred rapidly after meloxicam administration and was associated with the development of antinuclear antibodies suggesting a hypersensitivity mechanism. This first case of meloxicam related liver toxicity demonstrates the potential of this drug to induce hepatic damage.

MR imaging of hypervascular liver tumors: timing optimization during the arterial phase

To analyze the optimal timing strategy for the detection of hypervascular liver tumors during the arterial phase of magnetic resonance (MR) imaging, a test examination after injection of 2 mL of gadopentetate dimeglumine was performed in 47 patients. The time course of the tumor-to-liver contrast-to-noise ratio (CNR) for all studies together was determined relative to the start of injection, the time of peak aortic enhancement, and the time of peak enhancement in the tumor. All studies were grouped together and the highest CNR was transiently observed at the time of peak tumor enhancement. This CNR was significantly higher than those observed at fixed delays after peak aortic enhancement. However, the CNRs at peak tumor enhancement+/-1.5 seconds did not differ significantly from those obtained after peak aortic enhancement. Finally, the CNRs obtained at fixed delays after the start of injection remained significantly lower. In hypervascular liver tumors, a higher CNR can be obtained during the arterial phase when the MR imaging delay is determined relative to the time of peak enhancement in the tumor or the aorta rather than being fixed after the start of contrast material injection. Timing based on the enhancement profile in the tumor rather than in the aorta should be performed only if rapid MR imaging is available with a time resolution of about 1.5 seconds to image the whole liver.

CYP 3A proteins are expressed in human neutrophils and lymphocytes but are not induced by rifampicin

Cytochrome P-450 3A (CYP 3A) enzymes, the prominent subfamily in the cytochrome system, are expressed in various extrahepatic tissues. Until now, their expression has been demonstrated in human polymorphic neutrophils (PMNs) but not in lymphocytes using immunohistochemistry and immunoblot analysis. Moreover, their potential modulation has not been determined yet. To study such an expression in different peripheral blood cell populations, rifampicin (600 mg/day during 6 days) was given to 8 healthy subjects. PMNs and lymphocytes were isolated by centrifugation of whole white blood cell fractions using Ficoll gradients before drug administration, immediately after, and 3 days after drug withdrawal. PMN and lymphocyte smears and homogenates were subjected to immunostaining and immunoblotting, respectively, with a mouse monoclonal antibody recognizing all CYP 3A proteins. These proteins were quantified by densitometric analysis. Before and after rifampicin administration, a positive cytoplasmic staining was observed in all PMNs and in about 50% of lymphocytes. CYP 3A expression in lymphocytes was further confirmed by positive immunoblots for lymphocyte homogenates. Neither in PMNs nor in lymphocytes, induction of CYP 3A protein expression was observed after rifampicin treatment despite overall induction of CYP 3A activity assessed by the urinary excretion of 6beta-hydroxycortisol. These results demonstrate that CYP 3A proteins are constitutively expressed not only in PMNs but also in lymphocytes. However, in both cell lineages CYP 3A protein expression was not induced by rifampicin.

Severe exacerbation of liver disease during pregnancy in a thalassemic GBV-C/HGV-positive patient and neonatal hepatitis in offspring

The case of a young woman with GB virus C/hepatitis G virus (GBV-C/HGV) infection and with a severe exacerbation of chronic hepatitis of unknown etiology during pregnancy is described. In the offspring, severe neonatal hepatitis with subsequent mild chronic liver disease of at least 16-month duration was followed by the development of antibodies to the envelope protein (E2) of GBV-C/HGV, suggesting that the child was recovering from GBV-C/HGV infection. There was an improvement in clinical and biochemical parameters in the mother following delivery and alpha-interferon therapy was associated with a transient biochemical response.

Acute renal failure requiring haemodialysis after high doses percutaneous acetic acid injection for hepatocellular carcinoma

Recently, ultrasound-guided percutaneous acetic acid injection has been proposed in the treatment of hepatocellular carcinoma as an alternative to percutaneous ethanol injection. We report the case of severe renal failure requiring haemodialysis which occurred in a patient with 4 cm hepatocellular carcinoma treated adequately by high dose percutaneous acetic acid injection. The risk of such a serious side effect, likely related to a direct toxic effect of acetic acid, should be of concern when considering percutaneous treatment of hepatocellular carcinoma. Acute renal failure has been reported as a complication of acetic acid poisoning, but to our knowledge, we report here the first case of acute renal failure following high dose percutaneous acetic acid injection.

Influence of body mass index, sex and age on serum alanine aminotransferase (ALT) level in healthy blood donors

BACKGROUND AND AIM

Serum alanine aminotransferase (ALT) level is the most common screening test as part of a routine evaluation of liver damage. In order to determine the factors influencing this liver function test in normal subjects, the relationship between ALT level and gender, age and body mass index (BMI) was studied in a large population of healthy blood donors.

METHODS

This population included 9,420 volunteer blood donors (4,488 men and 4,932 women aged from 18 to 70 years) selected on the basis of negative answers to a detailed medical questionnaire including past medical history, drug and alcohol consumption, on the absence of clinical signs of liver disease, on the negativity of serological testing for hepatitis B and C virus and HIV.

RESULTS

In the overall population, the mean serum ALT value was 21.8 I.U./L and the mean BMI was 24.4 kg/m2. There was a positive significant correlation between serum ALT level and BMI (Pearson r = 0.54; p < 0.001) and between ALT and age (Pearson r = 0.25; p < 0.001). A major sex-difference in ALT value was observed, the mean ALT value being higher in men than in women (26.8 +/- 13.6 vs. 17.2 +/- 8.1 I.U./L, p < 0.0001). In both sexes, ALT level was significantly correlated with BMI (Pearson r = 0.45 in men and r = 0.37 in women; p < 0.001). In women a consistent rise in BMI and ALT value with increasing age was observed whereas in men BMI and ALT level only increased with age up to the fifth decade.

IN CONCLUSION

There was a significant positive correlation between ALT and BMI regardless the gender in a population of healthy volunteer blood donors. Moreover, at the same age and the same BMI, ALT was significantly lower in women than in men suggesting that the normal range for ALT value should be adjusted for gender. So gender and BMI have to be considered in the interpretation of ALT values.

Estimation of chlorzoxazone hydroxylase activity in liver microsomes and of the plasma pharmacokinetics of chlorzoxazone by the same high-performance liquid chromatographic method

We have developed a HPLC method which allows the determination of chlorzoxazone and its hydroxy metabolite in rat liver microsomes and in human plasma. We found that dehalogenated chlorzoxazone or 2-benzoxazolinone was a convenient and stable internal standard. Proteins were precipitated with diluted perchloric acid and the supernatant was extracted with ethyl acetate. Complete resolution of the peaks was achieved within 20 min with a Spherisorb ODS-1 column. The inter-day R.S.D.s were 6.5% at 0.5 microgram/ml of hydroxychlorzoxazone and 5.8% at 1 microgram/ml of chlorzoxazone in human plasma. The reproducibility of the method has been demonstrated for a large number of samples over a long period.

Is antiviral treatment (IFN alpha and/or ribavirin) justified in cirrhosis related to hepatitis C virus? Société Royale Belge de Gastro-entérologie

AIM

To assess the benefit risk ratio of interferon and ribavirin in the treatment of patients with post hepatitis C cirrhosis we summarize the spontaneous over mortality of this disease, and made an overview of the randomized trials and of other controlled studies.

RESULTS

In comparison to controls, patients with post hepatitis C cirrhosis have a 17 fold increase risk of dying from a liver disease that a control population, and a 6 fold increase from primary liver cancer. In France the hepatitis C epidemic which start in the sixties explains now the observed dramatic increase in mortality by primary liver cancer, both in men and women. Meta-analysis of randomized trials and controlled retrospective studies showed that interferon treatment is associated with a significant increase in ALT response at the end of the treatment, with a decrease in hepatocellular incidence as well as a decrease in mortality in comparison with controls. Very few data are published concerning ribavirin alone or in combination with interferon in patients with cirrhosis. Preliminary data suggest that this combination during 48 weeks permit to obtain in patients with compensated cirrhosis 20% of sustained virological response. The safety was acceptable but patients with low initial blood cells count must be carefully followed. In conclusion this overview clearly demonstrates a benefit-risk ratio in favor of treatment in patients with post hepatitis C cirrhosis by interferon.

Effect of hepatic insufficiency on pharmacokinetics and drug dosing

The liver plays a central role in the pharmacokinetics of many drugs. Liver dysfunction may not only reduce the plasma clearance of a number of drugs eliminated by biotransformation and/or biliary excretion, but it can also affect plasma protein binding which in turn could influence the processes of distribution and elimination. In addition, reduced liver blood flow in patients with chronic liver disease will decrease the systemic clearance of flow limited (high extraction) drugs and portal-systemic shunting may substantially reduce their presystemic elimination (first-pass effect) following oral administration. When selecting a drug and its dosage regimen for a patient with liver disease additional considerations such as altered pharmacodynamics and impaired renal excretion (hepatorenal syndrome) of drugs and metabolites should also be taken into account. Consequently, dosage reduction is necessary for many drugs administered to patients with chronic liver disease such as liver cirrhosis.

Effect of enteral versus parenteral feeding on hepatic blood flow and steady state propofol pharmacokinetics in ICU patients

OBJECTIVE

The main objective of this study was to evaluate the effect of switching from parenteral to enteral feeding on liver blood flow and propofol steady-state blood concentrations in patients in the intensive care unit (ICU).

DESIGN AND PATIENTS

Steady-state blood concentrations of propofol were measured in eight ICU patients before (on days D -3, D -2, and D -1) and after (on days D + 1, D + 2, and D + 3) switching from parenteral to enteral feeding (on day DO). All patients received a continuous intravenous infusion of propofol (4.5 mg x kg(-1) x h(-1)) from several days before the start of the study, continuing throughout the experimental period. Hepatic blood flow was estimated by measuring steady-state D-sorbitol hepatic clearance.

RESULTS

Hepatic blood flow was high and was not affected by switching from parenteral to enteral feeding: 33 +/- 8 ml x min(-1) x kg(-1) (mean +/- SD) and 33 +/- 10 ml min(-1) x kg(-1) on D -3 and D -1, respectively, as compared to 37 +/- 11 ml x min(-1) kg(-1) and 34 +/- 8 ml x min(-1) x kg(-1) on days D + 1 and D + 3, respectively. Systemic clearance of propofol was much higher than liver blood flow with average values on the six observation days ranging from 74.0 to 81.2 ml x min(-1) x kg(-1) and was not affected by switching from parenteral to enteral feeding.

CONCLUSIONS

Liver blood flow and systemic clearance of propofol were not affected by switching from parenteral to enteral feeding in the eight ICU patients studied. Extrahepatic clearance accounted for at least two thirds of the overall systemic clearance of propofol.

Inhibition of chlorzoxazone metabolism, a clinical probe for CYP2E1, by a single ingestion of watercress

To investigate the effect of watercress on the metabolism of chlorzoxazone, an in vivo probe for CYP2E1, the oral pharmacokinetics of chlorzoxazone was studied in 10 healthy volunteers before and after a single ingestion of a watercress homogenate (50 gm). A third chlorzoxazone pharmacokinetic study was performed after a 1-week treatment with isoniazid (300 mg/day), a well-known CYP2E1 inhibitor. Ingestion of watercress or isoniazid did not affect the oral absorption of chlorzoxazone. The area under the chlorzoxazone plasma concentration-time curve was significantly increased by 56% (p < 0.05) after watercress ingestion and by 135% (p < 0.001) with isoniazid treatment. Similarly, chlorzoxazone elimination half-life was prolonged after watercress (53%; p < 0.05) and isoniazid (104%; p < 0.01) administration. These results show that a single ingestion of watercress inhibits the hydroxylation of chlorzoxazone, an in vivo probe for CYP2E1.

Sensitive assay for midazolam and its metabolite 1'-hydroxymidazolam in human plasma by capillary high-performance liquid chromatography

A sensitive high-performance liquid chromatographic method is described for the quantification of midazolam and 1'-hydroxymidazolam in human plasma. Sample (1 ml plasma) preparation involved a simple solvent extraction step with a recovery of approximately 90% for both compounds. An aliquot of the dissolved residue was injected onto a 3 microm capillary C18 column (150 mm x 0.8 mm I.D.). A gradient elution was used. The initial mobile phase composition (phosphate buffer-acetonitrile, 65:35) was maintained during 16 min and was then changed linearly during a 1-min period to phosphate buffer-acetonitrile, 40:60. The flow-rate of the mobile phase was 16 microl/min and the eluate was monitored by UV detection. The limits of quantification for midazolam and 1'-hydroxymidazolam were 1 ng/ml and 0.5 ng/ml, respectively. The applicability of the method was demonstrated by studying the pharmacokinetics of midazolam, and its major metabolite 1'-hydroxymidazolam, in human volunteers following i.v. bolus administration of a subtherapeutic midazolam dose (40 microg/kg).

Reduction in hepatic cytochrome P-450 is correlated to the degree of liver fat content in animal models of steatosis in the absence of inflammation

BACKGROUND/AIM

Fatty liver has been associated with an increased risk of primary graft non-function and drug toxicity. However, these effects have been observed mainly in fatty liver with inflammation, a situation characterized by an overall reduction in cytochrome P-450 (CYP)-dependent activities as well as a contrasting increase in CYP2E1 activity. Our aim was to examine the impact of liver-fat accumulation on CYP in two animal models of fatty liver without necroinflammation.

METHODS

Ducks were force-fed with a high-glucidic diet and male Wistar rats, after 48 h fasting, were refed a high-glucidic, fat-free diet for 48 h. Total CYP, aminopyrine- (AND), erythromycin-N-demethylase (END) and chlorzoxazone hydroxylase (CZOHase) activities as well as CYP2E1 and CYP3A proteins were quantified on microsomal proteins.

RESULTS

Livers from force-fed ducks exhibited significant decreases in total CYP, AND, END and CZOHase activities, inversely correlated with fat-liver content. Refeeding male Wistar rats a high-glucidic, fat-free diet after 48 h fasting, resulting in a 235% increased liver fat content, was associated with a decrease in total CYP (55%), AND (78%), END (55%) and CZOHase (62%) activities as well as in CYP3A (70%) and CYP2E1 (80%) protein content. A significant inverse correlation was observed between CYP and total lipid content.

CONCLUSIONS

In these models of steatosis induced by nutritional manipulations, fat liver accumulation was associated with a significant decrease in CYP activities and in CYP protein expression. Furthermore, the decreases in both CYP content and related activities were correlated with the degree of liver fat content.

Inflammatory pseudotumor of the liver: MRI with mangafodipir trisodium

Inflammatory pseudotumor of the liver is a rare benign mass that is often misdiagnosed as hepatocellular carcinoma at preoperative imaging. We report a case of inflammatory pseudotumor of the liver with special emphasis on the appearance at MRI after administration of mangafodipir trisodium. On T1-weighted images the lesion was slightly hypointense relative to the liver, and on T2-weighted images it was isointense with a hyperintense capsule. No tumor enhancement was seen on T1-weighted images after administration of mangafodipir trisodium. MRI with mangafodipir trisodium might help to distinguish inflammatory pseudotumor of the liver from hepatocellular carcinoma.

Phenytoin hydroxylation in a healthy Caucasian population: bimodal distribution of hydroxyphenytoin urinary excretion

The phenytoin hydroxylation index was studied in 122 unrelated Caucasian volunteers. Following a 100 mg oral dose of phenytoin, phenytoin and hydroxyphenytoin were measured in urine from 0-32 hr after administration. As phenytoin was not found in all urine collections, a phenytoin hydroxylation index was expressed as follows: Phenytoin hydroxylation index = amount of phenytoin administered/0-32 hr urinary output of hydroxyphenytoin. Phenytoin hydroxylation index values appear to be bimodally distributed, 92% of the population showing a mean (+/- S.E.M.) value of 0.639 +/- 0.099 and 8% a mean (+/- S.E.M.) value of 1.001 +/- 0.180 (log10 values). These results are in favour of the existence of a phenytoin genetic polymorphism. Since misuse of urinary metabolite excretion data in drug metabolism studies is a well-known phenomenon, our data emphasize the need for future population studies on phenytoin pharmacokinetics as well as on CYP2C9 genotyping before concluding about existence of a phenytoin genetic polymorphism.

Acute lobular hepatitis as the first manifestation of recurrent autoimmune hepatitis after orthotopic liver transplantation

Recurrence of autoimmune hepatitis after orthotopic liver transplantation and after reduction in immunosuppressive treatment is reported in a 43-year-old man. Diagnosis was based on biological, serological and morphological data, as well as on a complete biological recovery following steroid resumption. Recurrence was observed only 4 months after transplantation, when an abrupt increase in liver function tests was observed in association with a mainly lobular hepatitis in liver biopsy. Such a histological appearance has been previously described in the case of recurrence after immunosuppressive treatment weaning in non-transplanted patients. In contrast, this histological feature has not been reported in the rare transplanted patients in whom such recurrence has been observed. Thereafter, the evolution of the disease in our patient remained slow, likely dampened by the administration of cyclosporine and azathioprine. Morphological features are detailed, and importance of immunosuppressive therapy in patients transplanted for end-stage autoimmune hepatitis is emphasized.

14C-Propoxyphene demethylation in the rat. An example of differences between liver and intestinal drug-presystemic metabolism

Presystemic metabolism is believed to occur mainly in the liver with some minor intestinal participation. The aim of this study was to investigate the respective part of each of these two organs in the metabolism of the analgesic d-propoxyphene (DP). Pharmacological doses of DP were given in the duodenum (ID), the portal vein (IP), and the femoral vein (IV) of male Wistar rats. A tracer dose of 14C-DP was also administered either in IV, IP, or ID as well as in hepatectomized rats or rats with bile duct diversion. In vitro demethylation occurring in liver and intestinal microsomes was also studied. Absolute DP bioavailability obtained after oral administration was two times higher than that observed after portal administration (48.9% vs. 23.2%, respectively), an result opposite (i.e. a lower bioavailability) of that expected on the basis of the existence of a liver enzyme saturation phenomenon. The 14CO2 cumulative excretion after 14C-DP administration was significantly lower after IV or ID administration than after injection in the portal vein as a bolus or within 20 min. The biliary excretion of the labeled compound varied in the opposite direction, being greater after IV or ID than after IP administration, suggesting that the metabolism of DP in the liver is influenced by an extrahepatic transformation. This most likely occurs in the gut since the production of 14CO2 after IV administration was similar to that after ID administration. This transformation did not prohibit DP detection in the systemic blood but was sufficient to increase the part eliminated with bile and to decrease the part demethylated into NP. Demethylation mainly occurs in the liver since the production of 14CO2 was nearly abolished in hepatectomized rats. Furthermore, microsomes of hepatic but not of intestinal origin were able to demethylate DP. Our data suggest that the transformation of DP occurring in gut after oral administration is responsible for changes in the hepatic metabolism of the drug.