Targeting the gut microbiota to treat alcoholic liver diseases: evidence and promises

The human intestine is colonized by a variety of microbes that influence the metabolic responses, the immune system and the nervous system. Dietary patterns are important factors that shape the composition of the gut microbiota. Many animal models of alcohol exposure have highlighted the key role of the alcohol-induced gut microbiota alterations, leaky gut and translocation of microbial products in the development of alcoholic liver disease (ALD). However, in humans, there is no clear picture defining an "alcoholic microbiome", and the link between intestinal dysbiosis and ALD development is far from being understood. Although we do not comprehend all the mechanistic insights, clinical studies aiming at modulating the gut microbiota of alcoholic patients have shown some beneficial effects. Here we review the potential therapeutic effects of probiotics in ALD and give some clinical perspectives on the role of prebiotics and the use of fecal microbiota transplantation.

[What is the role of the gut microbiota in the development of alcohol use disorders?]

Alcohol addiction is a complex and multifactorial disease influenced by social, psychological and biological aspects. The current pharmacological drugs used in the management of alcohol dependence have shown only a modest efficacy and the relapse rate remains high in this disease. Recently, the gut microbiota, a huge and dynamic ecosystem made up of billions of microorganisms living in our intestine, has been shown to regulate many important functions for human health. Indeed, the gut microbiota is known to influence our metabolism, our immune system as well as our nervous system with consequences for brain functions, mood and behaviour. We have shown that heavy and chronic alcohol consumption induced important changes in the composition of the gut microbiota. Furthermore, the microbial changes are associated with the severity of depression, anxiety and alcohol craving that are important factors predicting the risk of relapse. This suggests the existence of a gut-brain axis in alcohol dependence and supports the development of new therapeutic alternatives, targeting the gut microbiota, in the management of alcohol dependence.

Stopping nucleos(t)ide analogue treatment in Caucasian hepatitis B patients after HBeAg seroconversion is associated with high relapse rates and fatal outcomes

BACKGROUND

Stopping nucleos(t)ide analogues (NA) after hepatitis B e antigen (HBeAg) seroconversion is associated with high relapse rates in Asian patients, but data in Caucasian cohorts are scarce. Clinical course, outcomes and immunological aspects of chronic hepatitis B infections differ substantially between distinct ethnicities.

AIM

The aim of this study was to determine relapse rates, factors predicting relapse and clinical outcomes after nucleos(t)ide analogue cessation in a large, predominantly Caucasian cohort of chronic hepatitis B patients with nucleos(t)ide analogue-induced HBeAg seroconversion.

METHODS

This is a nationwide observational cohort study including HBeAg positive, mono-infected chronic hepatitis B patients with nucleos(t)ide analogue-induced HBeAg seroconversion from 18 centres in Belgium.

RESULTS

A total of 98 patients with nucleo(s)tide analogue-induced HBeAg seroconversion were included in the study. Of the 62 patients who stopped treatment after a median consolidation treatment of 8 months, 30 relapsed. Higher gamma-glutamyl transferase levels at both treatment initiation (HR 1.004; P = 0.001 per unit increment) and HBeAg seroconversion (HR 1.006; P = 0.013 per unit increment) were associated with an increased risk of clinically significant relapse in a multivariate Cox regression model. Treatment cessation led to liver-related death in 2 patients, of whom one showed a severe flare. Of the patients who continued treatment after HBeAg seroconversion, none relapsed or developed severe hepatic outcomes.

CONCLUSION

Treatment withdrawal in Caucasian chronic hepatitis B patients after nucleos(t)ide analogue-induced HBeAg seroconversion results in viral relapses in more than half of patients with potential fatal outcomes. These real-world data further lend support to preferentially continue NA treatment after HBeAg seroconversion until HBsAg loss.

Achieving WHO recommendations for Hepatitis C Virus Elimination in Belgium

BACKGROUD

The World Health Organization (WHO) released updated guidelines for the screening, care and treatment of patients with chronic hepatitis C virus (HCV) infection.

METHODS

A previously described HCV disease burden model was used to develop a "WHO scenario" to achieve the WHO recommendations of a 90% reduction in incidence and 65% reduction in liver-related deaths. After determining the steps necessary to achieve this goal, the impact of realistic constraints was modeled.

RESULTS

In 2015, there were 66.200 viremic infections, with 43% diagnosed and 1.350 treated. In order to reduce new infections, treatment must be extended to ≥ F0 patients, including people who inject drugs and other individuals at risk of transmitting HCV. -Additionally, diagnosis and treatment of 3.030 and 4.060 patients, respectively, would be required. The largest attenuation of the WHO scenario would occur if no new cases were diagnosed after 2018 (300% more viremic infections by 2030). Limiting treatment to ≥ F2 patients or treating fewer patients (3.000) would result in 220% or 140% more viremic cases, respectively, compared with the WHO scenario.

CONCLUSION

Achieving the WHO guidelines in Belgium requires a coordinated effort to scale up treatment and prevention efforts and to allow treatment access to patients of all fibrosis stages. A scale-up of treatment, however, requires patients to be both diagnosed and linked to care, suggesting a need for increased awareness and expanded screening efforts. Finally, prevention of new HCV infections requires a comprehensive understanding of the population at risk of transmitting HCV.

Alcohol-induced hypertension: an important healthcare target in Belgium

Excessive alcohol intake is one of the leading causes of premature death in Europe and particularly in Belgium. Belgian people are consuming more alcohol per year than the European average. It is well established that excessive alcohol consumption is a significant predictor of the development of hypertension (HTN). Two million adults in Belgium suffer from HTN and this number will increase to three million by 2025. Less than 50% of Belgian people treated for HTN are well-controlled. Alcohol reduction in patients with HTN can significantly lower systolic and diastolic blood pressure. After reviewing the epidemiology of HTN and alcohol disorders in Belgium, this paper will focus on the rationale for alcohol screening and brief intervention in primary care. It will also describe the barriers to alcohol screening, and what could be the benefits of alcohol screening for our healthcare system. The authors believe that early identification through alcohol screening and brief intervention in general practice can help to improve the management of patients with HTN, to reach the targets of the WHO Global Action Plan, i.e., a 25% relative reduction in the risk of premature mortality from cardiovascular diseases, cancer, diabetes or chronic respiratory diseases. They are also convinced that this would allow achieving major healthcare savings.

The Disease Burden of Hepatitis C in Belgium : An update of a realistic disease control strategy

BACKGROUND

This manuscript serves as an update to position papers published in 2014 based on the available Belgian hepatitis C virus (HCV) epidemiological data.

METHODS

Building on the current standard of care (2015 : 900 ≥ F3 patients treated with 70-85% SVR), four new scenarios were developed to achieve the goals of near viral elimination and prevention of HCV associated morbidity and mortality by 2026 and 2031. Increases in treatment efficacy were assumed in 2016 (90% SVR) and 2017 (95% SVR).

RESULTS

Scenario 1: Treating 6,670 patients annually by 2018 (≥ F0 beginning in 2017) and diagnosing 3,790 patients annually by 2020, a 90% reduction in viremic cases and advanced outcomes was observed by 2026. Scenario 2: Treating 4,300 patients annually by 2018 (≥ F0 beginning in 2020) without increasing the number diagnosed, a 90% reduction in viremic cases and 85%-95% reduction in advanced outcomes was observed by 2031. Scenario 3: Treating 5,000 ≥ F2 patients annually by 2018, and diagnosing 3,620 patients annually by 2020, a 90% reduction in advanced outcomes and 50% reduction in viremic cases was observed by 2026. Scenario 4: Treating 3,100 ≥ F2 patients annually by 2018 without increasing the number diagnosed, a 90%-95% reduction in advanced outcomes and 55% reduction in viremic cases was observed by 2031.

CONCLUSIONS

Scenario 2 would provide the most favorable balance of outcomes (90% reduction in viremic prevalence and advanced outcomes) and realistic requirements for implementation (gradual increase in treatment, delayed incorporation of patients with no/mild fibrosis).

The disease burden of hepatitis C in Belgium: development of a realistic disease control strategy

BACKGROUND

Novel direct antiviral agents (DAAs) will become available soon with higher sustained viral response (SVR), fewer side-effects and higher compliance. Our aim was to evaluate different realistic strategies to control the projected increase in HCV-related disease burden in Belgium.

METHODS

Based on literature review, expert opinions and historical assumptions, HCV-disease progression and mortality in Belgium was modeled to 2030. Strategies exploring the impact of increased treatment, treatment delay, and treatment restrictions were developed.

RESULTS

Although the overall HCV prevalence is decreasing in Belgium, the burden of advanced stage HCV, including cirrhosis and hepatocellular carcinoma (HCC), is expected to increase under current treatment and cure rates. By increasing SVR to 90% from 2016 onward and the number of treated cases (from 710 to 2,050), in 2030 the cases with cirrhosis, decompensated cirrhosis and HCC would be significantly lower than in 2013. This strategy was found most efficient when applied to F2-F4 cases. To obtain comparable outcomes with F0-F4 cases, 3,490 patients should be treated. A two year delayed access to the DAAs increased HCV related morbidity and mortality by 15% relative to our strategy.

CONCLUSIONS

Considering the evolving burden of HCV disease and the need for efficacious usage of healthcare resources, primary application of new DAAs in Belgium should focus on patients with significant and advanced fibrosis (F2-F4), providing these new drugs without delay upon availability and increasing access to therapy.

Hepatitis C epidemiology in Belgium

BACKGROUND

The burden of hepatitis C virus (HCV) infection is significant and is increasing with the aging population. The results of a modeling study that included Belgium, along with many other countries, was published in April 2014. An in depth discussion surrounding the epidemiology of HCV in Belgium will be presented here.

METHODS

A systematic literature review was conducted to assess the historical and current clinical burden of HCV in Belgium. Two expert panels were convened to discuss the strengths and limitations surrounding the available data and to generate consensus regarding the best estimates for total number of HCV cases, number of cases diagnosed, and the number of patients treated and cured, including potential HCV control strategies.

RESULTS

Although no national studies exist, there were an estimated 70,000 (10,000-91,000) viremic HCV infections in 1994. By 2010 there were an estimated 22,900 individuals diagnosed with viremic HCV, and in 2011 approximately 710 patients were treated annually. An estimated 13% of liver transplants were attributable to HCV in 2011. Genotype 1 predominated (59%), followed by genotypes 3 (19%) and 4 (14%).

CONCLUSIONS

Estimates of HCV prevalence, diagnosed cases and liver transplants due to HCV were available through published studies. However these publications were subject to bias and were occasionally outdated. Improved estimates of HCV prevalence would be useful for informing treatment, prevention and policy efforts in Belgium.

Current and future health and economic impact of hepatitis C in Belgium

BACKGROUND AND STUDY AIMS

Chronic hepatitis C virus (HCV) infection is a serious global health problem affecting 150 million individuals worldwide. Although infection rates are decreasing, an aging population with progressing disease is expected to result in increased burden of advanced stage disease with high associated costs. This analysis describes the current and projected future economic impact of HCV sequelae in Belgium.

METHODS

A previously described and validated model was populated with Belgian inputs and calibrated to project the current and future health and economic burden of HCV. Monte Carlo and sensitivity analyses were run to quantify uncertainty. All estimates exclude the cost of antiviral therapy.

RESULTS

Costs associated with HCV were projected to peak in 2026 at Euro126M (Euro30M-Euro257M), while decompensated cirrhosis and hepatocellular carcinoma costs were projected to increase until 2031 and 2034. The projected 2014-2030 cumulative cost of HCV under current conditions was Euro1,850M. Scenarios to reduce the burden of HCV could result in Euro70M-Euro400M in cumulative cost savings. Starting treatment (1,000 patients) in 2015 could result in Euro150M cost savings. The lifetime cost of HCV increases with life expectancy, with highest future costs projected among young females with early stage disease.

CONCLUSIONS

The economic burden of HCV and advanced stage disease were projected to further increase. Cost reductions are possible with timely interventions aimed at minimizing the health burden of advanced stage disease.

Historical epidemiology of hepatitis C virus (HCV) in selected countries

Chronic infection with hepatitis C virus (HCV) is a leading indicator for liver disease. New treatment options are becoming available, and there is a need to characterize the epidemiology and disease burden of HCV. Data for prevalence, viremia, genotype, diagnosis and treatment were obtained through literature searches and expert consensus for 16 countries. For some countries, data from centralized registries were used to estimate diagnosis and treatment rates. Data for the number of liver transplants and the proportion attributable to HCV were obtained from centralized databases. Viremic prevalence estimates varied widely between countries, ranging from 0.3% in Austria, England and Germany to 8.5% in Egypt. The largest viremic populations were in Egypt, with 6,358,000 cases in 2008 and Brazil with 2,106,000 cases in 2007. The age distribution of cases differed between countries. In most countries, prevalence rates were higher among males, reflecting higher rates of injection drug use. Diagnosis, treatment and transplant levels also differed considerably between countries. Reliable estimates characterizing HCV-infected populations are critical for addressing HCV-related morbidity and mortality. There is a need to quantify the burden of chronic HCV infection at the national level.

The present and future disease burden of hepatitis C virus (HCV) infection with today's treatment paradigm

The disease burden of hepatitis C virus (HCV) is expected to increase as the infected population ages. A modelling approach was used to estimate the total number of viremic infections, diagnosed, treated and new infections in 2013. In addition, the model was used to estimate the change in the total number of HCV infections, the disease progression and mortality in 2013-2030. Finally, expert panel consensus was used to capture current treatment practices in each country. Using today's treatment paradigm, the total number of HCV infections is projected to decline or remain flat in all countries studied. However, in the same time period, the number of individuals with late-stage liver disease is projected to increase. This study concluded that the current treatment rate and efficacy are not sufficient to manage the disease burden of HCV. Thus, alternative strategies are required to keep the number of HCV individuals with advanced liver disease and liver-related deaths from increasing.

Strategies to manage hepatitis C virus (HCV) disease burden

The number of hepatitis C virus (HCV) infections is projected to decline while those with advanced liver disease will increase. A modeling approach was used to forecast two treatment scenarios: (i) the impact of increased treatment efficacy while keeping the number of treated patients constant and (ii) increasing efficacy and treatment rate. This analysis suggests that successful diagnosis and treatment of a small proportion of patients can contribute significantly to the reduction of disease burden in the countries studied. The largest reduction in HCV-related morbidity and mortality occurs when increased treatment is combined with higher efficacy therapies, generally in combination with increased diagnosis. With a treatment rate of approximately 10%, this analysis suggests it is possible to achieve elimination of HCV (defined as a >90% decline in total infections by 2030). However, for most countries presented, this will require a 3-5 fold increase in diagnosis and/or treatment. Thus, building the public health and clinical provider capacity for improved diagnosis and treatment will be critical.

Chemoprevention of hepatocellular carcinoma. Proof of concept in animal models

In the present work, we have evaluated the possibility of preventing liver carcinogenesis in rats at two stages of development. In the first series of experiments, we induced foci of altered hepatocytes, (FAH) which represent the first events in rodent liver carcinogenesis, using the chemical mutagens diethylnitrosamine (DEN) and acetylaminofluorene (AAF). In the second part of the work, we used repeated weekly injections of DEN only that gave rise to significant fibrosis at 11 weeks and the development of malignant tumours at 16 weeks. We chose to assess the chemopreventive effect of three different drugs: pioglitazone, lanreotide and S-trans-trans-farnesylthiosalicylic acid (FTS). Pioglitazone (PGZ) is an agonist of peroxisome proliferator-activated receptor gamma (PPARg), itself a member of the nuclear receptor superfamily, responsible for the modulation of a number of metabolic pathways, including cell differentiation, metabolism of lipids and inflammation. Lanreotide (LAN) is a somatostatin analogue that has an inhibitory effect on the release of several hormones, such as growth hormone and serotonine. FTS is a specific antagonist of the protoocogene Ras, tested here based on the rationale that Ras is activated in many hepatocellular carcinomas (HCC). We showed that both PGZ and LAN were efficient in the first, pre-neoplastic model, by reducing the size of FAH, decreasing proliferation specifically in FAH by interacting with proteins of the cell cycle. We could also demonstrate that LAN increased apoptosis. In the second model, LAN was able to diminish the number of established HCC by decreasing proliferation, in parallel with an anti-fibrotic action. Furthermore, enhanced apoptosis and antiangiogenic effects were observed when LAN was given from the start of the carcinogenic induction by DEN. The cellular mechanisms leading to its effects warrant further investigations. FTS also strongly inhibited the appearance of FAH and HCC in the second model, through a complete inhibition of Ras activation and the induction of pro-apoptotic pathways. On the contrary, PGZ did not prevent the appearance of neoplastic lesions. For these reasons, we did not analyse further its mechanism of action in the second model. Altogether, the results we obtained demonstrate an activity of both LAN and FTS, at the early onset of liver carcinogenesis, and later on when advanced fibrosis, cirrhosis and HCC are induced. These anti-tumoural effects could be complementary and will be tested in combination in the future.

Foetal 'flat' bile acids reappear during human liver regeneration after surgery

BACKGROUND

Changes in bile acid (BA) pool, such as the reappearance of typically foetal-type molecular species with a 'flat' structure at the steroid ring, occur during hepatocarcinogenesis, both in humans and rodents. Moreover flat-BAs also appear during rat liver regeneration. These changes can be detected in urine. The aim of the present study was to investigate whether flat-BAs also reappear during human liver regeneration, and whether this change correlates with the magnitude of liver resection.

MATERIALS AND METHODS

Patients undergoing partial hepatectomy were divided in two groups: major hepatectomy group (> 50% of hepatic tissue resection, n = 17) and minor hepatectomy group (< 50%, n = 13). BAs were extracted from serum and urine (collected over 24 h) and analysed by gas chromatography-mass spectrometry. Samples were obtained before surgery (day 0) and on the third and seventh days after hepatectomy.

RESULTS

In serum, total BAs significantly increased on day seven after hepatectomy, but only a moderate increase in flat-BA concentrations was observed. By contrast, urinary excretion of total as well as flat-BAs significantly increased at day three and day seven after hepatectomy. Moreover, the amount of flat-BAs excreted in urine during the first week after partial hepatectomy correlated with the magnitude of the resection.

CONCLUSIONS

Urinary BA output increases and flat-BAs reappear in urine during human liver regeneration. These results suggest that determination of BAs in urine may be an interesting parameter obtained by non-invasive techniques whose actual clinical value during human liver regeneration warrants further evaluation.

Alcohol dependence is associated with reduced plasma and fundic ghrelin levels

BACKGROUND

Conflicting data concerning the involvement of ghrelin in the pathophysiology of alcohol dependence have been reported. The aim of this study is to investigate how chronic alcohol ingestion influences plasma ghrelin levels and whether potential changes observed in plasma relate to modifications in ghrelin production in the stomach where this peptide is primarily synthesized.

MATERIALS AND METHODS

Fifty-one consecutive alcoholics admitted for alcohol withdrawal were prospectively enrolled and compared to a control group of 32 healthy volunteers matched for age, sex, height and weight. All subjects underwent fasting plasma ghrelin determination. Twenty-seven randomly selected alcoholics and 17 controls underwent gastroscopy for fundic and duodenal biopsies. Tissues were fixed for histology or frozen in liquid nitrogen for ghrelin protein and mRNA determinations by a radioimmunoassay and quantitative polymerase chain reaction, respectively. Alcohol consumption was normalized to body weight (BW) or body mass index (BMI) given the influence of BW and volume distribution on alcohol levels.

RESULTS

Plasma and fundic ghrelin protein levels were significantly decreased in alcoholics. Fundic but not plasma ghrelin protein levels inversely correlated with alcohol consumption normalized to BW or BMI. Ghrelin mRNA levels in fundic biopsies were similar in alcoholics and controls. No significant differences in duodenal ghrelin protein and mRNA levels were found between both groups.

CONCLUSIONS

Alcoholism was associated with decreased plasma ghrelin levels partly due to reduced ghrelin production in the stomach. Alcohol affected ghrelin production on the post-transcriptional level in the fundus, whereas duodenal ghrelin secretion did not respond in a similar manner to alcohol intake.

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.

The management of patients with mild hepatitis C

Infection with the hepatitis C virus (HCV) represents an important public health problem and is a leading cause of chronic hepatitis, cirrhosis and hepatocellular carcinoma. Chronic hepatitis C is a heterogeneous disease. Many patients have mild disease at presentation but not all of them will develop advanced liver disease. However, the identification of these patients with mild hepatitis C who will show progressive disease is difficult and is based on histological criteria and the assessment of co-factors (age, alcohol intake, steatosis). In addition, serum transaminases that are persistently normal on several occasions during 18 months may point to a more benign course. Patients with mild hepatitis C should not be excluded "a priori" from the possibility of being treated, as treatment with pegylated interferon and ribavirin is safe and effective in this group. Overall, the decision to initiate therapy should be individualized and based on the severity of the disease by liver biopsy, the potential of serious side effects, the probability of response and the motivation of the patient.

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.

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.

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.

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.

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.