Interferon-induced depression in chronic hepatitis C

Since the success rate of the antiviral treatment of chronic hepatitis C (HCV) is increasing, the knowledge of side effects due to this therapy must also improve. Among these side effects, depression and other neuro-psychiatric symptoms are among the most important. It must be outlined that conditions may exist before treatment in relation to the viral infection. However, pegylated interferon (IFN) administration is associated with a huge increase in the importance and the incidence of neuro-psychiatric symptoms. This has led several experts to claim that antiviral therapy should not be given to HCV patients having psychiatric contraindications. This last assertion seems to be disproved on the basis of results of recent clinical trials using selective serotonin reuptake inhibitors (SSRI). Pathogenesis of these neuro-psychiatric symptoms, however, remains unknown although the impact of IFN on glucocorticoid receptors and on serotonin 1A receptors is privileged. In conclusion, advances in HCV antiviral therapy and the comprehension and subsequent treatment of side effects induced by this therapy should allow us to treat more patients with greater success.

Limited therapeutic efficacy of pioglitazone on progression of hepatic fibrosis in rats

AIM

Peroxisome proliferator activated receptor gamma (PPARgamma) agonists have been shown to prevent hepatic fibrosis in rodents. We evaluated the therapeutic antifibrotic potential of the PPARgamma agonist pioglitazone on established hepatic fibrosis.

METHODS

Repeated injections of carbon tetrachloride (CCl4), a choline deficient diet, or bile duct ligation (BDL) were used to induce hepatic fibrosis in rats. Pioglitazone treatment was introduced at various time points. Therapeutic efficacy was assessed by comparison of the severity of hepatic fibrosis in pioglitazone treated versus untreated fibrotic controls.

RESULTS

When introduced after two weeks of CCl4, pioglitazone reduced hepatic fibrosis, OH proline content, hepatic mRNA expression of collagen type I, and profibrotic genes, as well as the number of activated alpha smooth muscle actin positive hepatic stellate cells, compared with rats receiving CCl4 only, with no significant change in necroinflammation. When pioglitazone treatment was initiated after five weeks of CCl4, no antifibrotic effect was observed. Similarly, pioglitazone was associated with a reduced severity of fibrosis induced by a choline deficient diet when introduced early, while delayed treatment with pioglitazone remained ineffective. In contrast, pioglitazone failed to interrupt progression of fibrosis due to BDL, irrespective of the timing of its administration.

CONCLUSION

In rats, the therapeutic antifibrotic efficacy of pioglitazone is limited and dependent on the type of injury, duration of disease, and/or the severity of fibrosis at the time of initiation of treatment.

Oligofructose promotes satiety in healthy human: a pilot study

OBJECTIVE

The administration of a fermentable dietary fibre (oligofructose) in rats increases satietogenic gut peptides and lowered spontaneous energy intake. The aim of the study was to assess the relevance of those effects of oligofructose on satiety and energy intake in humans.

DESIGN

Single-blinded, crossover, placebo-controlled design, pilot study.

SUBJECTS

Volunteers included five men and five women aged 21-39 years, BMI ranging from 18.5 to 27.4 kg/m(2), were randomly assigned as described below.

INTERVENTIONS

Subjects were included in two 2-week experimental phases during which they received either fibre (oligofructose (OFS)) or placebo (dextrine maltose (DM)); a 2-week washout period was included between crossover phases. In total, 8 g OFS or 8 g DM were ingested twice daily (16 g/day in total). Energy intake, hunger, satiety, fullness and prospective food consumption were assessed with analogue scales at the end of each experimental phase.

RESULTS

During breakfast, OFS significantly increases the satiety (P=0.04) without any difference on other sensations as compared to DM treatment periods. After lunch, no significant differences are observed between treatment period. At dinner, OFS significantly increases satiety (P=0.04), reduces hunger (P=0.04) and prospective food consumption (P=0.05). The energy intake at breakfast and lunch are significantly lower (P=0.01, 0.03, respectively) after OFS treatment than after DM treatment. Total energy intake per day is 5% lower during OFS than in DM period.

CONCLUSION

Oligofructose treatment increases satiety following breakfast and dinner, reduces hunger and prospective food consumption following dinner. This pilot study presents a rationale to propose oligofructose supplements in the management of food intake in overweight and obese patients.

Lamivudine for nephrotic syndrome related to hepatitis B virus (HBV) infection

A 57-year-old man presented with nephrotic syndrome associated with active HBV infection. Liver biopsy showed severe portal and moderate lobular inflammation, patchy necrosis, moderate fibrosis and several "ground glass" cells. Immunofluorescence microscopical view of the renal biopsy showed diffuse granular IgG deposits along the glomerular basement membrane, compatible with MN. As symptomatic therapy with ACE inhibitors did not improve the nephrotic syndrome, lamivudine 100 mg o.d. was initiated. HBV-DNA became undetectable after 10 weeks and seroconversion of HBeAg and HBsAg to anti-HBe and anti-HBs occurred after 2 additional months; proteinuria normalized subsequently. This observation documents for the first time in an adult the beneficial effect of lamivudine in glomerulonephritis related to HBV infection with HBV seroconversion and complete remission of the nephrotic syndrome.

Hypervitaminosis A-induced liver fibrosis: stellate cell activation and daily dose consumption

Hypervitaminosis A-related liver toxicity may be severe and may even lead to cirrhosis. In the normal liver, vitamin A is stored in hepatic stellate cells (HSC), which are prone to becoming activated and acquiring a myofibroblast-like phenotype, producing large amounts of extracellular matrix.

AIMS

In order to assess the relationship between vitamin A intake, HSC activation and fibrosis, we studied nine liver biopsies from patients belonging to a well-characterized series of 41 patients with vitamin A hepatotoxicity.

METHODS

Fibrosis was underlined by Sirius-red staining, whereas activated HSC were immunohistochemically identified using an antibody against alpha smooth muscle actin. The volume density (Vv) of sinusoidal and total fibrosis and of sinusoidal and total activated HSC was quantified by the point-counting method.

RESULTS

Morphology ranged from HSC hypertrophy and hyperplasia as the sole features to severe architectural distortion. There was a significant positive correlation between Vv of perisinusoidal fibrosis and the daily consumption of vitamin A (P=0.004).

CONCLUSION

The close correlation between the severity of perisinusoidal fibrosis and the daily dose of the retinol intake suggests the existence of a dose-effect relationship.

Effects of oligofructose on glucose and lipid metabolism in patients with nonalcoholic steatohepatitis: results of a pilot study

OBJECTIVE

In experimental animals, recent results suggest that the addition of inulin-type fructans such as oligofructose (OFS) in the diet decreases triacylglycerol accumulation in the liver tissue. Therefore, we have investigated the effect of daily ingestion of OFS in seven patients with nonalcoholic steatohepatitis (NASH), confirmed by liver biopsies.

DESIGN

They received 16 g/day OFS or maltodextrine (placebo) for 8 weeks in a randomized double-blind crossover design. Energy intake, body composition, liver steatosis and blood parameters were analysed after 4 and 8 weeks of dietary supplementation.

RESULTS

Compared to placebo, OFS decreased significantly serum aminotransferases, aspartate aminotransferase after 8 weeks, and insulin level after 4 weeks, but this could not be related to significant effect on plasma lipids.

CONCLUSION

This pilot study supports the putative interest of OFS in the management of liver diseases associated with abnormal lipid accumulation in humans.

Molecular events associated with accelerated proliferative response in rat livers when partial hepatectomy is preceded by a sham operation

BACKGROUND

When a sham operation is performed 6 h before partial hepatectomy (PH), the regenerative response is accelerated suggesting that sham operation itself contributes to cellular events leading to proliferation.

MATERIALS AND METHODS

In order to examine the mechanisms implicated in this acceleration, we compared the activation of several factors associated with the progression through the cell cycle at various times after PH and after PH preceded by sham operation (S6 h + PH). The effect of a single sham (S) and two combined sham operations (S6 h + S) was also examined. Nonoperated rats were used as controls (C).

RESULTS

The early factors NF-kappaB and Stat3 were activated after S6 h + PH and S6 h + S. C-jun expression was increased 0.5 h and 2 h after PH and 6 h after sham. There was no further increase in S6 h + PH and S6 h + S. In contrast, c-myc expression returned to baseline levels after S6 h and a new increase was observed 2 h after S6 h + PH but not after S6 h + S. P53 mRNA was significantly expressed 6 h after S6 h + PH, but at a level similar than that observed 6 and 12 h after PH alone. An earlier increase in c-Ha-ras mRNA and cyclin E protein was found in S6 h + PH, in comparison with PH alone.

CONCLUSIONS

The first divergent response between the two combined models involved c-myc expression. However, major differences related to the accelerated liver regenerative response observed after S6 h + PH were found at late time points associating an earlier expression of c-Ha-ras and nuclear cyclin E.

Adult liver transplantation at UCL: update 2002

The authors present the results of a single centre study of 587 liver transplants performed in 522 adults during the period 1984-2002. Results have improved significantly over time due to better pre-, peri- and post-transplant care. One, five, ten and fifteen year actuarial survivals for the whole patient group are 81.2; 69.8; 58.9 and 51.2%. The high incidence of de novo tumors (12.3%), of cardiovascular diseases (7.5%) and of end-stage renal function (3.6%) should be further incentives to tailor the immunosuppression to the individual patient and to direct the attention of the transplant physician to the long-term quality of life of the liver recipient.

Daily induction combination treatment with alpha 2b interferon and ribavirin or standard combination treatment in naive chronic hepatitis C patients. A multicentre randomized controlled trial

The standard treatment for patients with chronic hepatitis C is a 6-12-month combination therapy with interferon alpha and ribavirin. Induction treatment could result in a faster early decline of the hepatitis C virus (HCV) load and a better response rate. Naive chronically infected HCV patients (n = 454) were randomized into two arms to receive either induction treatment with interferon alpha 2b 5 million units (MU) subcutaneously (s.c.) daily during a period of 8 weeks (arm A); or treatment with interferon alpha 2b 5 MU s.c. three times a week (TIW) for a period of 8 weeks (arm B). After week 8, interferon treatment in both arms was 3 MU s.c. TIW for a total period of 12 months. In both arms, ribavirin (1000-1200 mg orally per day) was added at week 4. Induction treatment resulted in a higher virological response at week 8 of treatment (66%vs 47%; P < 0.01). However, response at the end of treatment and at 6 months follow-up was not different (53%vs 50%, 41%vs 33%). The occurrence of adverse events and the drop-out rate were similar in both arms. Although an early virological response is observed more frequently in the induction treatment, end of treatment response and sustained responses did not differ.

[Multidetector CT and MRI of benign liver tumors]

With multidetector helical CT, the entire liver can be imaged rapidly with thin slices. High temporal and spatial resolution is important to improve multiphase examinations of the liver. The need to perform multiphase examinations to diagnose benign liver tumors should, however, be assessed by keeping in mind the risk of radiation and contrast-induced adverse events. MRI offers several advantages relative to CT. Excellent contrast resolution is obtained. Multiphase examinations can be performed in all patients. Reticuloendothelial contrast agents may be useful to characterize benign tumors. Several benign liver tumors, particularly hemangiomas and lesions of focal nodular hyperplasia, can be characterized with CT and MRI. Histologic examination is still needed to characterize some benign liver tumors.

Differential induction of midazolam metabolism in the small intestine and liver by oral and intravenous dexamethasone pretreatment in rat

1. Midazolam is metabolized in the rat by CYP3A enzymes to 4-OH-midazolam (4-OH-MDZ) and 1'-OH-midazolam (1'-OH-MDZ). The induction of midazolam metabolism was studied in male Wistar rats treated with dexamethasone (50 mg kg(-1) day(-1)) during 4 days via the oral or intravenous routes. Microsomes were prepared from the liver and the proximal small intestine and in vitro metabolism of midazolam was determined. In addition, CYP3A1- and CYP3A2-like protein levels were measured by gel electrophoresis and immunoblotting. 2. The V(max)'s (mean SEM) for 4-OH-MDZ and 1'-OH-MDZ formation were much lower in intestinal (0.078 +/- 0.002 and 0.074 +/- 0.002 microM min(-1) mg(-1) protein, respectively) compared with hepatic microsomes prepared from the uninduced rat (0.870 +/- 0.007 and 0.310 +/- 0.020 microM min(-1) mg(-1) protein, respectively). Induction by oral or intravenous dexamethasone pretreatment led to significant increases in V(max) for 4-OH-MDZ and 1'-OH-MDZ by both intestinal and hepatic microsomes. Oral dexamethasone pretreatment via the oral route resulted in a more pronounced increase in V(max) compared with intravenous administration of the inducer. 3. CYP3A1 and CYP3A2 protein levels in liver microsomes were significantly increased following oral (3.7- and 3.2-fold, respectively) or intravenous (2.6- and 2.1-fold, respectively) pretreatment with dexamethasone. On the contrary, only oral dexamethasone pretreatment resulted in a significant change in intestinal CYP3A2-like protein (7.3-fold). A slight difference in the migration distance of the immunoreactive band for CYP3A2 was also observed for intestinal microsomes. 4. These results suggest that intestinal CYP3A enzymes in the rat differ from hepatic CYP3A1 and CYP3A2. They also demonstrate that systemic dexamethasone administration can induce intestinal microsome activity.

Interaction between azathioprine and aminosalicylates: an in vivo study in patients with Crohn's disease

BACKGROUND

The inhibition of thiopurine methyltransferase activity, one of the enzymes responsible for azathioprine metabolism, by aminosalicylates has been described in an in vitro study. This could result in a higher risk of bone marrow depression when using the two drugs together.

AIM

To investigate the in vivo interaction between azathioprine and aminosalicylates in quiescent Crohn's disease by measuring 6-thioguanine nucleotide levels, thiopurine methyltransferase activity and the plasma levels of the acetylated metabolite of 5-aminosalicylic acid.

METHODS

Sixteen patients taking a stable dose of azathioprine, plus sulfasalazine or mesalazine, were enrolled and completed the study. They were not taking any drugs interfering with azathioprine metabolism. Four visits every 4 weeks were held over a 3-month period. Aminosalicylate administration was withdrawn after the second visit. At each visit, the blood cell count, inflammatory parameters, levels of 6-thioguanine nucleotide and the acetylated metabolite of 5-aminosalicylic acid and thiopurine methyltransferase activity were determined.

RESULTS

After aminosalicylate withdrawal, mean 6-thioguanine nucleotide levels decreased significantly from 148 pmol (57-357 pmol) to 132 pmol (56-247 pmol) per 8 x 10(8) red blood cells (P=0.027), without significant changes in thiopurine methyltransferase activity or biological parameters.

CONCLUSIONS

This in vivo study favours the existence of an interaction between azathioprine and aminosalicylates through a mechanism which remains unclear. This drug-drug interaction should be taken into account when using azathioprine and aminosalicylates simultaneously.

Assessment of hepatic perfusion parameters with dynamic MRI

Quantification of hepatic perfusion parameters greatly contributes to the assessment of liver function. The purpose of this study was to describe and validate the use of dynamic MRI for the noninvasive assessment of hepatic perfusion parameters. The signal from a fast T(1)-weighted spoiled gradient-echo sequence preceded by a nonslice-selective 90 degrees pulse and a spoiler gradient was calibrated in vitro with tubes filled with various gadolinium concentrations. Dynamic images of the liver were obtained after intravenous bolus administration of 0.05 mmol/kg of Gd-DOTA in rabbits with normal liver function. Hepatic, aortic, and portal venous signal intensities were converted to Gd-DOTA concentrations according to the in vitro calibration curve and fitted with a dual-input one-compartmental model. With MRI, hepatic blood flow was 100 +/- 35 mL min(-1) 100 mL(-1), the arterial fraction 24 +/- 11%, the distribution volume 13.0 +/- 3.7%, and the mean transit time 8.9 +/- 4.1 sec. A linear relationship was observed between perfusion values obtained with MRI and with radiolabeled microspheres (r = 0.93 for hepatic blood flow [P < 0.001], r = 0.79 for arterial blood flow [P = 0.01], and r = 0.91 for portal blood flow [P < 0.001]). Our results indicate that hepatic perfusion parameters can be assessed with dynamic MRI and compartmental modeling.

Haptoglobin phenotype 2-2 overrepresentation in Cys282Tyr hemochromatotic patients

BACKGROUND/AIMS

Patients with genotypic Cys282Tyr homozygous hemochromatosis differ largely in phenotypic presentation. The HFE mutation on itself does not explain the different manifestations of hemochromatosis. We hypothesized that the genetic haptoglobin (Hp) polymorphism, because of its effect on iron metabolism, could be a modifying factor that influences the clinical presentation of hereditary hemochromatosis.

METHODS

In 167 Cys282Tyr homozygous hemochromatotic patients, the frequencies of Hp types (1-1, 2-1 and 2-2) and alleles (Hp1, Hp2) were compared with those in 918 healthy subjects. Clinical and laboratory indices of iron overload were incorporated in the analysis.

RESULTS

The Hp 2-2 type was overrepresented in the patient group (P<0.01). Male patients carrying Hp 2-2 had higher serum iron (P=0.003) and ferritin levels (P=0.03) than those with a Hp 1-1 or 2-1 type. The amount of iron removed with phlebotomy was also higher in Hp 2-2 patients (P=0.03).

CONCLUSIONS

The Hp 2-2 type is overrepresented among Cys282Tyr homozygous hemochromatotic patients. At diagnosis, iron overload was more pronounced in male patients carrying Hp 2-2. Our data suggest that Hp polymorphism affects iron metabolism in hereditary hemochromatosis.

Favorable outcome of orthotopic liver transplantation in a patient with subacute liver failure due to the emergence of a hepatitis B YMDD escape mutant virus

BACKGROUND/AIMS

Patients with end-stage liver disease due to chronic hepatitis B infection in whom a YMDD escape hepatitis B virus (HBV) mutant has emerged under lamivudine treatment are generally denied liver transplantation (OLT).

METHODS

We report the case of a male patient who was started on prophylactic treatment with lamivudine in the context of recurrent episodes of HBV reactivation during high dose immunosuppressive therapy for relapsing severe pulmonary sarcoidosis.

RESULTS

Following the emergence of a YMDD escape mutant virus under lamivudine treatment, he developed subacute liver failure requiring liver transplantation. The patient was treated with a combination of intravenous hepatitis B immune globulin (HBIG) which was started perioperatively and also continued lamivudine after OLT. Twelve months after OLT, there was no evidence of HBV reinfection of the liver graft with the use of HBIG and lamivudine.

CONCLUSIONS

This observation suggests that emergence of the YMDD mutation is not a contra-indication to OLT, providing adequate immunoprophylaxis using HBIG and lamivudine combination therapy.

Intravenous omeprazole in critically ill patients: a randomized, crossover study comparing 40 with 80 mg plus 8 mg/hour on intragastric pH

OBJECTIVE

To compare intravenous omeprazole 40-mg single dose with 8 mg/hr after an 80-mg bolus injection on 24-hr intragastric pH in intensive care unit (ICU) ventilated patients.

DESIGN

Prospective, randomized crossover study.

SETTING

A 42-bed medicosurgical ICU in a university hospital

PATIENTS

Medicosurgical ventilated patients at risk of gastrointestinal bleeding.

INTERVENTIONS

After baseline determination of intragastric pH, patients were randomly allocated to have a 40-mg iv omeprazole bolus injection (arm I) or 80 mg bolus, followed by 8 mg/hr continuous infusion for 24 hrs (arm II). After a 24-hr washout period, the opposite regimen was given in a crossover design. Intragastric pH was determined at regular intervals during the treatment period.

RESULTS

In ten patients completing the protocol, the intragastric pH was similar for the two regimens for the first 12 hrs. The area under the pH curve was 5.51 +/- 0.48 for arm I compared with 6.02 +/- 0.33 for arm II (NS). Time to reach a pH of 4 or 6 was not significantly different for the two regimens. Time spent with a pH greater than 4 and 6 for the first 12 hrs was 10.11 +/- 1.14 and 8.31 +/- 1.16 hrs vs. 10.11 +/- 0.75 and 7.43 +/- 1.19 hrs for arm I and arm II, respectively (NS). When the first 24 hrs are considered, the area under the pH curve was 5.17 +/- 0.49 for arm I vs. 6.36 +/- 0.25 for arm II (p <.05). Time spent with a pH greater than 4 and 6 was 17.2 +/- 2.4 hrs and 12.63 +/- 2.22 vs. 23 +/- 0.41 and 19.48 +/- 1.63 in arm I and arm II, respectively (p <.05 and.01). An intragastric pH above 6 for all determinations was only observed in arm II.

CONCLUSIONS

In critically ill patients, intravenous omeprazole 40 mg single dose is as effective as 8 mg/hr after an 80-mg bolus injection on mean intragastric pH, time spent with a pH greater than 4 and 6, but only for the first 12 hrs. If an intragastric pH greater than 6 has to be maintained for 24 hrs in all patients, an 80-mg bolus followed by 8 mg/hr iv omeprazole is to be given. Our data suggest that in several critically ill patients, a single 40-mg iv omeprazole bolus injection may be able to achieve stress ulcer prophylaxis and that 40 mg twice daily should be compared with 8 mg/hr after an 80-mg bolus injection in bleeding ulcers.

Expression of presumed specific early and late factors associated with liver regeneration in different rat surgical models

Experiments performed on the portal branch ligation (PBL) model indicate that early changes observed after surgery are not related to the regenerative process because they also occur in atrophying lobes. To further confirm the lack of specificity of the early events and to exclude the influence of circulatory factors released by proliferating lobes on their occurrence, we investigated this response after sham operation (SO) and portacaval shunt (PCS), a model characterized by liver atrophy. We also attempted to determine expression of later events associated specifically with regeneration, ie, expression of p53 or c-Ha-ras, or inhibition of proliferation, ie, interleukin-1beta (IL-1beta) and transforming growth factor-beta1 (TGF-beta1) after partial (PH) and temporary partial (TPH) hepatectomy, SO and PCS. Nuclear factor-kappaB (NF-kappaB) and signal transducer and activator of transcription 3 (STAT3) DNA binding were assessed by electrophoretic mobility shift assay (EMSA), interleukin-6 (IL-6) mRNA by reverse transcription-polymerase chain reaction (RT-PCR), c-myc and c-jun mRNAs by Northern blot analysis at 0.5 and 2 hours, p53 and c-Ha-ras mRNAs by Northern blot analysis at 8 and 24 hours, and IL-1beta and TGF-beta1 by RT-PCR at 24 hours. The early response including an increase of NF-kappaB, STAT3, IL-6, and immediate-early genes expression was present after PH, PCS, and SO. In SO, slight differences were observed in comparison with PH: no NF-kappaB p65/p50 DNA binding was observed, only three of six SO rats were positive for IL-6, and immediate-early genes induction showed differences in the intensity of the response. At later times, p53 mRNA increased at 8 hours after PH and TPH, c-Ha-ras mRNA at 24 hours after PH, and IL-1beta mRNA at 24 hours after PCS. Early events are not specifically associated with the reduction of liver mass or with the regenerative process, are not predictive of future cell fate, and are most likely related to surgical stress. p53 and c-Ha-ras induction is closely associated with cell cycle progression whereas IL-1beta, but not TGF-beta1, appears to be one of the negative growth regulators that might play an important role in atrophy.

Recurrent immuno-allergic hepatitis related to amoxicillin-clavulanic acid

We report on a patient who presented, on 2 occasions at one-year interval after a treatment with the amoxicillin-clavulanic acid association, a clinical and biological picture in keeping with the diagnosis of immuno-allergic hepatocellular hepatitis. On liver biopsies, the most characteristic finding was portal and lobular eosinophilic infiltration without cholestasis and biliary ducts damage.

After portal branch ligation in the rat, cellular proliferation is associated with selective induction of c-Ha-ras, p53, cyclin E, and Cdk2

BACKGROUND

In liver regeneration after portal branch ligation we previously showed that early cellular changes are observed in both the proliferating and atrophying liver lobes. They are therefore not indicative of future proliferative response. In this study we attempted to define precisely, in the same model, the time at which the cellular processes diverge between the lobes by measuring various parameters associated with cellular proliferation. We also investigated the possible role of inhibitors of cell proliferation in the absence of progression towards the S phase in the atrophying lobes.

AIMS

Expression of p53, c-Ha-ras, cyclin E, cyclin dependent kinase (Cdk2), transforming growth factor (TGF)-beta, and interleukin (IL)-1alpha and IL-1beta were assessed in relation to their potential role in proliferating and atrophying cellular phenomenons.

METHODS

Immunohistochemistry, northern blotting, western blotting, and reverse transcription-polymerase chain reaction were performed, mainly at time points corresponding to mid-G1/S phase progression (8-24 hours after surgery).

RESULTS

The common and thus most likely non-specific response was still evident 5-8 hours after surgery and included an increase in IL-1 mRNA as well as p53 and cyclin E proteins. From 12 hours onwards, p53, c-Ha-ras, cyclin E, and Cdk2 were selectively induced in proliferating lobes whereas IL-1beta was predominantly activated in atrophying lobes. No changes in TGF-beta or IL-1alpha expression were observed at the same time points in any of the liver lobes.

CONCLUSIONS

The initial response to portal branch ligation and thus probably to partial hepatectomy seems to be non-specific for at least eight hours. Thereafter, p53, c-Ha-ras, cyclin E, and Cdk2 seem to drive cellular proliferation while IL-1beta is associated with cellular atrophy. In contrast, TGF-beta and IL-1alpha do not seem to play a role in determining the commitment of cells towards atrophy or proliferation.

Midazolam and cortisol metabolism before and after CYP3A induction in humans

INTRODUCTION

CYP3A is responsible for the metabolism of numerous endogenous and exogenous compounds. Several substrates of CYP3A have been investigated to assess the CYP3A-metabolizing capacity of an individual in an attempt to predict the rate of metabolism of other CYP3A substrates. Two such tests of CYP3A activity are the midazolam plasma clearance after its intravenous administration and the 6beta-OH cortisol urinary ratio. Possible correlations between these 2 tests were investigated before and after treatment with rifampin in a group of healthy volunteers.

METHODS

Pharmacokinetic parameters of midazolam and 6beta-OH cortisol urinary ratio were evaluated in 8 volunteers before and after 6 days treatment with rifampin, a potent inducer of CYP3A, and after cessation of rifampin treatment.

RESULTS

Midazolam systemic clearance and the 6beta-OH cortisol urinary ratio were significantly higher at Days 7 and 10 than at Day 0. There was a strong positive correlation between these 2 parameters (r = 0.70, p < 0.001). In contrast, no correlation was observed between the ratio of the AUCs of 1'-OH midazolam vs. midazolam (AUC0-1(1'-OH)/AUC0-t(MDZ)) or the ratio of plasma concentration of 1'-OH midazolam vs. midazolam (C30 min(1'-OH)/C30 min(MDZ)) and the 6beta-OH cortisol urinary ratio (r = 0.05, p = 0.82; r = 0.04, p = 0.88, respectively). Considering only data obtained before or after treatment with rifampin, however, no correlation was observed between midazolam systemic clearance and the 6beta-OH cortisol urinary ratio.

CONCLUSIONS

These data demonstrate that there is a strong positive correlation between systemic midazolam clearance and 6beta-OH cortisol urinary ratio before and after induction. This suggests that the 6beta-OH cortisol urinary ratio test is a non-invasive alternative to the use of systemic midazolam clearance for monitoring the time-course of CYP3A induction.

Cryopreservation of rat precision-cut liver slices by ultrarapid freezing: influence on phase I and II metabolism and on cell viability upon incubation for 24 hours

Several cryopreservation methods for precision-cut rat liver slices (PCLS) have been proposed, allowing a short-term (a few hours) maintainance of viability and functionality upon thawing. The aim of the present study was to test the metabolic capacity of PCLS cryopreserved by an ultrarapid method. The biotransformation of paracetamol to its glucuronide and sulfate conjugates and of midazolam to its hydroxylated metabolites was studied in thawed PCLS incubated for 24 hours at 37 degrees C in Williams' medium E. In addition, protein levels of the key enzymes involved in these metabolic reactions, i.e. UGT1A1, ST1A1, CYP2E1 and CYP3A2 were determinated. In addition, biological markers of cell function (ATP and glycogen levels) and toxicity (LDH leakage in the medium) were also measured. Compared to controls (non cryopreserved PCLS), CYP3A2 activity and content and CYP2E1 content were maintained at the same level all along the incubation, whereas paracetamol glucuronidation and sulfation dropped to 24 and 21% of the control value, respectively, immediately after thawing. Freezing-thawing conditions also modified cell functionality, leading to a lower intracellular ATP and glycogen content, and an increase in cell lysis, as shown by LDH released in the medium. The results of this study suggest that cryopreserved PCLS are able to maintain some phase I activities for 24 hours after thawing whereas some phase II metabolic capacities are not maintained.