Adjusted estimate of the prevalence of hepatitis delta virus in 25 countries and territories

BACKGROUND & AIMS

Hepatitis delta virus (HDV) is a satellite RNA virus that requires the hepatitis B virus (HBV) for assembly and propagation. Individuals infected with HDV progress to advanced liver disease faster than HBV-monoinfected individuals. Recent studies have estimated the global prevalence of anti-HDV antibodies among the HBV-infected population to be 5-15%. This study aimed to better understand HDV prevalence at the population level in 25 countries/territories.

METHODS

We conducted a literature review to determine the prevalence of anti-HDV and HDV RNA in hepatitis B surface antigen (HBsAg)-positive individuals in 25 countries/territories. Virtual meetings were held with experts from each setting to discuss the findings and collect unpublished data. Data were weighted for patient segments and regional heterogeneity to estimate the prevalence in the HBV-infected population. The findings were then combined with The Polaris Observatory HBV data to estimate the anti-HDV and HDV RNA prevalence in each country/territory at the population level.

RESULTS

After adjusting for geographical distribution, disease stage and special populations, the anti-HDV prevalence among the HBsAg+ population changed from the literature estimate in 19 countries. The highest anti-HDV prevalence was 60.1% in Mongolia. Once adjusted for the size of the HBsAg+ population and HDV RNA positivity rate, China had the highest absolute number of HDV RNA+ cases.

CONCLUSIONS

We found substantially lower HDV prevalence than previously reported, as prior meta-analyses primarily focused on studies conducted in groups/regions that have a higher probability of HBV infection: tertiary care centers, specific risk groups or geographical regions. There is large uncertainty in HDV prevalence estimates. The implementation of reflex testing would improve estimates, while also allowing earlier linkage to care for HDV RNA+ individuals. The logistical and economic burden of reflex testing on the health system would be limited, as only HBsAg+ cases would be screened.

IMPACT AND IMPLICATIONS

There is a great deal of uncertainty surrounding the prevalence of hepatitis delta virus among people living with hepatitis B virus at the population level. In this study, we aimed to better understand the burden in 25 countries and territories, to refine techniques that can be used in future analyses. We found a lower prevalence in the majority of places studied than had been previously reported. These data can help inform policy makers on the need to screen people living with hepatitis B virus to find those coinfected with hepatitis delta virus and at high risk of progression, while also highlighting the pitfalls that other researchers have often fallen into.

Viral dominance patterns in chronic hepatitis delta determine early response to interferon alpha therapy

Chronic hepatitis D is caused by coinfection of hepatitis B and hepatitis D virus. While HDV is the dominant virus over HBV in the majority of cases, mechanisms and consequences of viral dominance are largely unknown. We aimed to investigate associations between viral dominance patterns and patients' characteristics and inflammatory features; 109 HDV-infected patients treated with PEG-IFNa-2α within the international multicentre, prospective HIDIT-2 trial were studied. Patients were classified as D- or B-dominant if the viral load of one virus exceeded that of the other virus by more than 1log₁₀ . Otherwise, no viral dominance (ND) was described. We used Luminex-based multiplex technology to study 50 soluble immune mediators (SIM) in pretreatment samples of 105 HDV RNA-positive patients. Dominance of HDV was evident in the majority (75%) of cases. While only 7% displayed B-dominance, 17% showed nondominance. D-dominance was associated with downregulation of 4 interleukins (IL-2ra, IL-13, IL-16 and IL-18) and 5 chemokines/cytokines (CTACK (CCL27), MCP-1 (CCL2), M-CSF, TRAIL and ICAM-1) while no analyte was increased. In addition, D-dominance could be linked to a delayed HDV RNA response to pegylated interferon as patients with B-dominance or nondominance showed higher early HDV RNA responses (61% at week 12) than D-dominant patients (11%; P < .001). In conclusion, this study revealed unexpected effects of viral dominance on clinical and immunological features in chronic hepatitis delta patients. Individualizing PEG-IFNa-2α treatment duration should consider viral dominance. Overall, our findings suggest an activated but exhausted IFN system in D-dominant patients.

Long-term entecavir or tenofovir disoproxil fumarate therapy in treatment-naïve chronic hepatitis B patients in the real-world setting

The aim of this study was to determine the long-term efficacy of entecavir (ETV) and tenofovir disoproxil fumarate (TDF) on the natural course of disease in chronic hepatitis B patients (CHB) with/without cirrhosis in clinical practice. A total of 355 treatment-naïve CHB patients were enrolled into the study. The primary outcome measure was viral suppression as defined by serum HBV DNA level <20 IU/mL. A secondary outcome measure was to determine the development of Hepatocellular carcinoma (HCC). Virological and biochemical responses were similar between the two treatment groups over time. The presence of cirrhosis and hepatitis B e antigen (HBeAg) positivity did not appear to impact viral suppression. The cumulative probability of HBeAg loss was 41% at 4 years of therapy. Hepatitis B surface antigen (HBsAg) loss occurred in four patients. Model for End-Stage Liver Disease score was significantly improved from baseline to week 48 and 96 under antiviral therapy (P = 0.013, P = 0.01). HCC was diagnosed in 17 patients (4.8%). The cumulative probability of the development of HCC was 3.3% at 1 year and 7.3% at 4 years of therapy. The development of HCC was independently associated with older age (P = 0.031) and the presence of cirrhosis (P = 0.004). Serum creatinine levels and creatinine clearance remained stable over time. ETV and TDF effectively maintained virological and biochemical responses in long-term follow-up of CHB patients with/without cirrhosis. HCC may still develop, although at a lower rate, and is more likely to develop in patients with cirrhosis, especially in older patients.

Tumour necrosis factor-alpha, interleukin-10, interferon-gamma and vitamin D receptor gene polymorphisms in patients with chronic hepatitis delta

No data exist to assess certain polymorphisms that have a potential effect on the immune response in patients with chronic hepatitis delta (CHD). The aim of this study was to investigate polymorphisms in 6 polymorphic sites: IL-10 -1082 (rs1800896), IL-10 -627 (rs1800872), IFN-γ +874 (rs62559044), TNF-α -308 (rs1800629), vitamin D receptor (VDR) FokI (rs2228570) and VDR TaqI (rs731236). The genotypes of 67 patients with CHD and 119 patients with chronic hepatitis B (CHB) were compared. In addition, 56 individuals with resolved hepatitis B virus (HBV) infection were used as a control group for patients with CHB. Polymorphisms in TNF-α, IL-10, and VDR genes were analysed using polymerase chain reaction/restriction fragment length polymorphism methods. The IFN-γ gene polymorphism was detected by allele-specific polymerase chain reaction (PCR). Patients with CDH were more likely to have advanced liver disease compared with patients with CHB (P < 0.0001). IL-10 -1082 and VDR TaqI polymorphisms showed significant differences between patients with CHD and CHB. The high secretory IL-10 -1082 genotype GG was less frequent in CHD compared with patients with CHB and resolved HBV (17.7%, 37.4% and 47.1%, respectively (P < 0.05 for CHD vs CHB and resolved HBV). The frequency of the high secretory VDR TaqI TT genotype was 86.6% in patients with CHD, 62.7% in patients with CHB and 62.5% in resolved HBV individuals (CHD vs CHB: P < 0.05). None of the polymorphisms analysed had an effect on HBV persistence. IL-10 -1082 and VDR TaqI polymorphisms may contribute to the more severe liver disease associated with CHD compared with CHB.

Randomized clinical trial: efficacy and safety of telbivudine and lamivudine in treatment-naïve patients with HBV-related decompensated cirrhosis

Patients with decompensated cirrhosis owing to chronic hepatitis B viral (HBV) infection have a high morbidity/mortality rate, and the treatment remains a challenge. We studied the safety and efficacy of telbivudine and lamivudine in such patients. This noninferiority, double-blind trial randomized 232 treatment-naive patients with decompensated HBV (1:1) in 80 academic hospitals to receive once-daily telbivudine 600 mg or lamivudine 100 mg for 104 weeks. Primary composite endpoint was proportion of patients with HBV DNA <10 000 copies/mL, normal alanine aminotransferase (ALT) and Child-Turcotte-Pugh score improvement/stabilization at week 52. Response rates using a post hoc modified endpoint (HBV DNA <300 copies/mL [57 IU/mL] and ALT normalization) in intent-to-treat analysis (missing = failure) were 56.3%vs 38.0% after 76 weeks (P = 0.018) and 45.6%vs 32.9% after 104 weeks (P = 0.093) for telbivudine vs lamivudine. Telbivudine treatment was an independent predictive factor for HBV DNA <300 copies/mL and ALT normalization (P = 0.037). Response rates with protocol-defined composite endpoint in intent-to-treat analysis (M = F) were 56.2 vs 54.0% (noninferiority not achieved) and 39.1%vs 36.4% (noninferiority achieved) in telbivudine and lamivudine groups at 52 and 104 weeks. Telbivudine treatment was associated with a significant improvement in glomerular filtration rate compared to lamivudine treatment and was also associated with a trend for improvement in survival (87%vs 79%). No cases of lactic acidosis were reported. Telbivudine compared to lamivudine was associated with a higher rate of patients with both viral suppression and ALT normalization, a trend towards a higher rate of survival and significant improvement in glomerular filtration.

Renal function during treatment with adefovir plus peginterferon alfa-2a vs either drug alone in hepatitis B/D co-infection

Long-term safety of treatment with hepatitis B virus (HBV) polymerase inhibitors is a concern. Adefovir dipivoxil (ADV) therapy has previously been associated with impairment of renal function. Limited data are available on the safety of combination therapy with nucleos(t)ide analogues and interferon alfa (IFNα). The aim of this analysis was to assess the renal function during combination therapy with peginterferon alfa-2a (PegIFNα-2a) plus ADV vs either drug alone in patients with hepatitis B/D co-infection. We performed a retrospective analysis of renal function data of patients treated in the Hep-Net/International Delta Hepatitis Intervention Trial 1(HIDIT-1-trial), a European multicenter study to investigate the efficacy of 48 weeks of therapy with PegIFNα-2a+ADV vs either drug alone in 90 patients with chronic hepatitis B/D co-infection. Glomerular filtration rates (GFR) were calculated by Cockcroft-Gault (CG), abbreviated Modification of Diet in Renal Disease (MDRD) study and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. After 48 weeks of therapy GFR values were significantly lower in patients receiving adefovir-containing treatment vs PegIFNα-2a alone [mean difference 16.1 mL/min (CG) and 10.2 mL/min (MDRD), respectively, P < 0.05] while no differences were observed between patients receiving adefovir alone vs combination treatment. Twenty-four weeks after treatment GFR values did not differ between treatment arms. A decrease in GFR ≥ 20% was observed more often in patients during adefovir-containing treatment vs PegIFNα-2a alone (P < 0.05) which was confirmed by Kaplan-Meier analysis. Adefovir-containing but not PegIFNα-2a treatment was associated with a decrease in GFR values in about one-fifth of patients. Combination treatment of PegIFNα-2a+ADV in chronic hepatitis B/D co-infection did not lead to any further impairment of kidney function.

Hepatitis B surface antigen seroconversion is associated with favourable long-term clinical outcomes during lamivudine treatment in HBeAg-negative chronic hepatitis B patients

The aims of this study were to assess hepatitis B surface antigen (HBsAg) seroconversion and to determine its impact on the natural course of the disease in patients with HBeAg-negative chronic hepatitis B (CHB) during lamivudine (LMV) treatment. A total of 183 consecutive patients with HBeAg-negative CHB who were treated with LMV were included in the study. Data were retrospectively collected from outpatient visit charts. The primary endpoint was HBsAg seroconversion to anti-HBs. The secondary endpoint was to determine the development of cirrhosis. Loss of HBsAg was confirmed in 10 patients and seroconversion to anti-HBs in nine patients during LMV treatment or after its discontinuation. HBsAg seroconversion was achieved on-treatment in four patients after a median treatment duration of 30 months and off-treatment in the remaining five patients in a median 61 months after LMV discontinuation. The cumulative probability of HBsAg seroconversion increased from 0.6% at 1 year and 1.9% at 5 years to 21.5% at 10 years of LMV during and after LMV treatment. HBsAg clearance was preceded by undetectable serum hepatitis B virus (HBV) DNA. The majority of the patients responding to treatment had undetectable HBV DNA levels at 24 weeks of treatment. The cumulative probability of LMV resistance increased from 2.2% at 1 year to 37.3% at 5 years. No baseline parameter predicting either HBsAg seroconversion or the emergence of LMV resistance was identified. None of the patients with HBsAg seroconversion experienced virological breakthrough or disease progression during the follow-up period. These results indicate that HBsAg seroclearance can occur in patients with HBeAg-negative CHB under LMV therapy and predicts better clinical outcome.

A short course of add-on adefovir dipivoxil treatment in lamivudine-resistant chronic hepatitis B patients

The aims of the study were to investigate the efficacy of rescue therapy with lamivudine (LAM) and adefovir (ADV) combination for 6 months followed by ADV monotherapy in lamivudine-resistant chronic hepatitis B (LAM-R CHB) patients, and to analyze the frequency of ADV resistance mutant development in such patients. A total of 170 consecutive LAM-R CHB patients (male/female: 130/40, mean age: 42.9+/-13.4 years) with viral breakthrough under LAM therapy were analyzed. A total of 68 had HBeAg-positive. Patients received rescue therapy with LAM [100 mg (qd)]+ADV [10 mg (qd)] for 6 months after which LAM was discontinued. HBV-DNA was assessed with the HBV-DNA 3.0 bDNA assay. ADV-resistant mutations were identified by sequencing the reverse transcriptase region. The median duration of rescue therapy was 24 months. Cumulative probability of becoming HBV-DNA undetectable was 33.8%, 59.6% and 68.2% after 24, 48 and 96 weeks of treatment, respectively. These figures were 43.2%, 58.0% and 73.1% for ALT normalization. Among 68 HBeAg-positive CHB patients, 10 patients had an e-antigen seroconversion. Low baseline HBV-DNA level (<10(7) copies/mL) was a significant predictor of response to ADV treatment (P<0.01). Cumulative probability of ADV resistance was 1.2%, 15.1% and 37.3% at 12, 24 and 36 months of therapy, respectively. By multivariate analysis, baseline high viral load and primary nonresponse to treatment at week 24 predicted ADV resistance. The data indicate that a time limited add-on strategy does not provide benefit over the switch strategy with respect emergence of ADV resistant mutants in LAM-R CHB patients.

Treatment of chronic delta hepatitis with lamivudine vs lamivudine + interferon vs interferon

Chronic delta hepatitis is the most severe form of chronic viral hepatitis for which interferon (IFN) is the only available treatment. In 39 patients (25 were treatment-naïve, 14 had previously used IFN), efficacy of 1-year treatment with IFN (9 MU, t.i.w.) or lamivudine (LAM; 100 mg, q.d.) alone was compared with IFN and LAM combination (2 months of LAM to be followed by combination treatment). IFN monotherapy was given only to treatment-naïve patients. In both treatment-naïve and previous IFN users, end of treatment virological and biochemical responses were similar with IFN-LAM combination and superior to LAM monotherapy (P < 0.05). Improvement in liver histology occurred more often with IFN +/- LAM than with LAM alone (P < 0.05). In treatment-naïve patients, combination treatment was not superior to IFN monotherapy. After treatment discontinuation, virological and biochemical response rates decreased in LAM and IFN combination and IFN monotherapy. On treatment virological response at month 6 of treatment predicted sustained virological response. The results of this study suggest that addition of LAM to IFN for the treatment of delta hepatitis is of no additional value and that both treatment modalities are superior to LAM monotherapy.

A pilot study of 2 years of interferon treatment in patients with chronic delta hepatitis

High dose interferon treatment for 1 year is the only established treatment for chronic hepatitis D, but it is associated with a high relapse rate after treatment discontinuation. In this study, patients were treated with 10 MU interferon alpha 2b, thrice weekly for 2 years. Twenty-three patients were recruited and 15 completed the 2-year treatment and 6 months follow-up periods. Treatment response was assessed biochemically [normal alanine aminotransferase (ALT)], virologically (undetectable hepatitis D virus RNA) and histologically (at least 2 point decrease in the Knodell score) at the end of treatment (EOT) and at the end of follow-up. Out of 15 patients who finished the 2-year treatment period, seven patients (47%) had a biochemical response but only two (13%) had a normal ALT after follow-up. ALT decreased from the baseline value of 143.1 +/- 121.7 (mean +/- SD) to 39.7 +/- 20.6 (P < 0.01) at EOT. Virological response was observed in six patients at EOT and in two patients at follow-up. Two patients lost hepatitis B surface antigen. Of the 12 patients with paired liver biopsies, a histological improvement was observed in eight patients. Interferon treatment leads to a complete or partial response in a substantial number of patients but 2 years of treatment does not appear to increase sustained response rates over 1 year treatment.

Predicting response to peginterferon alpha-2a, lamivudine and the two combined for HBeAg-negative chronic hepatitis B

OBJECTIVE

In a trial of patients with hepatitis B e antigen (HBeAg)-negative chronic hepatitis B, 24 week post-treatment biochemical and virological response rates with peginterferon alpha-2a with or without lamivudine were significantly higher than with lamivudine alone. The effect of pre-treatment factors on post-treatment responses was investigated.

METHODS

Multivariate analyses were performed using available data from 518 patients treated with peginterferon alpha-2a with or without lamivudine, or with lamivudine alone. A post-treatment response was defined as alanine aminotransferase (ALT) normalisation and hepatitis B virus (HBV) DNA level of <20,000 copies/ml.

RESULTS

In logistic regression analyses across all treatment arms, peginterferon alpha-2a (with or without lamivudine) therapy, younger age, female gender, high baseline ALT, low baseline HBV DNA and HBV genotype were identified as significant predictors of combined response at 24 weeks post-treatment. In the peginterferon alpha-2a and lamivudine monotherapy arms, patients with genotypes B or C had a higher chance of response than genotype D infected patients (p<0.001), the latter responding better to the combination than to peginterferon alpha-2a monotherapy (p = 0.015). At 1 year post-treatment, response rates by intention-to-treat analysis were 19.2% for the peginterferon alpha-2a, 19.0% for the combination, and 10.0% for the lamivudine groups, with genotypes B or C associated with a sustained combined response to peginterferon alpha-2a with or without lamivudine therapy.

CONCLUSIONS

Baseline ALT and HBV DNA levels, patient age, gender, and infecting HBV genotype significantly influenced combined response at 24 weeks post-treatment, in patients treated with peginterferon alpha-2a and/or lamivudine. At 1 year post-treatment HBV genotype was significantly predictive of efficacy for patients treated with peginterferon alpha-2a with or without lamivudine.

Inhibition of hepatitis B virus replication by shRNAs in stably HBV expressed HEPG2 2.2.15 cell lines

In this study, the effect of RNAi on HBV replication was observed in a cell culture model, HepG2 2.2.15 cell line, which supports human HBV ayw replication and expression. Aim of the study was to investigate effects of shRNAs (small hairpin RNAs) targeting hepatitis B virus mRNAs on the viral replication in HepG2 2.2.15 cells. We selected three target HBV mRNA regions with different putative secondary structures to test whether the secondary structure of RNA may affect the inhibition efficacy on the target HBV RNA. Three HBV-specific siRNAs (small interfering RNA) were designed targeting X (1689-1708), Core (2229-2248) and S (765-784 nt) transcripts. HepG2 2.2.15 cells were transfected with shRNA expressing plasmids, P765, P2229 and P1689 targeting S, core and X region, respectively or a mock plasmid targeting lacZ gene. The culture media was collected throughout six days after transfection and analyzed by real-time PCR. Viral DNA production was suppressed for 7 days. The HBV DNA levels were decreased by 73, 72 and 79% with P765, P2229 and P1689 vectors, respectively. In conclusion, the shRNAs designed for X, core and S regions, specifically and significantly suppressed HBV DNA. siRNAs potentially may be used in treatment of hepatitis B.

Cytotoxic CD4 T cells in viral hepatitis

CD4+ T cells are thought to contribute to antiviral immune responses by secretion of cytokines thereby providing help to CD8+ T and B cells. However, perforin-positive cytotoxic CD4+ T cells have been described in human immunodeficiency virus-positive patients suggesting a role not only of CD8+ but also of CD4+ T cells for killing virus-infected cells. We investigated 76 patients with viral hepatitis [15 hepatitis B virus (HBV), 22 HBV/hepatitis D virus and 17 hepatitis C virus (HCV)] for cytotoxic CD4+ T cells. The frequency of perforin-positive CD4+ T cells in viral hepatitis was highly variable ranging from < 1% to more than 25%. Perforin-positive CD4+ T cells displayed the phenotype of terminally differentiated effector cells (CD28-, CD27-). The highest frequencies of CD4+ cytotoxic T lymphocytes (CTLs) were found in patients with delta hepatitis (P = 0.04 vs HBV and HCV patients), and the presence of CD4+ CTLs was associated with elevated aspartate aminotransferase levels (P = 0.01) and decreased platelet counts (P = 0.03). Perforin-positive CD4+ T cells decreased in two individuals during spontaneous clearance of acute hepatitis C. Significant associations were found between the frequency of perforin-expressing CD4+ cells and age (P = 0.04), perforin-positive CD8+ cells (P < 0.001) and perforin-positive CD4-/CD8- lymphoid cells (P = 0.002). Differentiated CD27- effector CD4+ CTLs can be detected in patients with viral hepatitis. In particular in patients with more advanced liver disease, the accumulation of perforin-positive T cells with age could be one correlate for the more severe course of viral hepatitis in elderly individuals.

Lamivudine vs lamivudine and interferon combination treatment of HBeAg(-) chronic hepatitis B

To determine whether combination treatment of HBeAg(-) chronic hepatitis B is beneficial we studied 78 patients with HBeAg(-), HBV DNA-positive chronic hepatitis B who were randomized to lamivudine, 100 mg, qd, for 12 months or lamivudine-interferon (9 MU, t.i.w.) in combination. In the combination arm, 2 months of lamivudine treatment preceded 10 months of combination treatment. Biochemical, virologic and histologic responses were assessed at the end of treatment, after six and a median 27 months of drug-free follow-up (short- and long-term follow-up, respectively). Virologic response was defined as undetectable HBV DNA with a hybridization assay and biochemical response as normal alanine aminotransferase (ALT). Change in HBV DNA was also assessed by real-time polymerase chain reaction (PCR). Presence of YMDD mutants at the end of treatment was investigated with a line probe assay. Both treatment regimes led to a median 2 log decline in HBV DNA levels. Virologic end of treatment responses were 90 and 92% with mono- and combination treatment, respectively. Corresponding virologic responses at short- and long-term follow-up were 59 and 54%, and 27 and 25%, respectively. Patients having a baseline HBV DNA value > or =200 pg/mL were more likely to relapse within 6 months off therapy than those patients with a baseline HBV DNA level <200 pg/mL (P = 0.041). YMDD mutants were observed in 53% of patients receiving lamivudine compared with 24% of patients receiving the combination regime (P = 0.017). In conclusion, efficacy of combination treatment is similar to lamivudine monotherapy. However, combination treatment decreases the development of YMDD mutant strains compared with lamivudine monotherapy.

Molecular epidemiology of hepatitis B, C and D viruses in Turkish patients

Different genotypes of the hepatitis viruses may influence the clinical outcome of the disease. The distribution of genotypes may vary according to geographical regions. The aim of this study was to evaluate hepatitis B virus (HBV), hepatitis C virus (HCV) and hepatitis D virus (HDV) genotypes in Turkish patients with chronic hepatitis in a large cohort of patients. Genotyping was performed in 41, 59 and 365 patients with chronic hepatitis B, D and C, respectively, and 36 hemodialysis patients with chronic hepatitis C. Genotypes were determined by direct sequencing in hepatitis B and by polymerase chain reaction-restriction fragment length polymorphism in hepatitis C and D patients. In addition, HBV subtyping by multiplex PCR and subtype specific ELISA were performed in 83 and 71 HBsAg (+) blood donors, respectively. All hepatitis B (100%) and hepatitis D (100%) patients had genotype D and type I, respectively. HBsAg subtyping by two methods yielded that 99% of the patients were subtype ayw. S gene amino acid sequence in the 41 patients included for HBV genotyping revealed the ayw2 subtype. Genotype distribution of 365 patients with chronic C hepatitis were as follows: 306 (84%) patients genotype 1b, 43 (11%) patients genotype 1a, 10 (3%) patients genotype 2, 3 (1%) patients genotype 3, 3 (1%) patients genotype 4. Among 36 patients receiving hemodialysis, 28 (78%) patients had genotype 1b and 8 (22%) patients had genotype 1a. The study indicates that Turkish patients with chronic viral hepatitis show very little genotypic heterogeneity. Subtype ayw and the genotype D of HBV DNA, and the type I of HDV RNA represent almost 100% of related infections. The genotype 1b of HCV RNA was found to be significantly dominant in Turkish patients.

Ligand-induced expression of peroxisome proliferator-activated receptor alpha and activation of fatty acid oxidation enzymes in fatty liver

BACKGROUND

Peroxisome proliferator-activated receptor alpha (PPARalpha) regulates lipid metabolism upon activation by ligands. Peroxisome proliferator-activated receptor alpha may play a role in the pathogenesis of fatty liver disease. The aim of this study was to assess the PPARalpha expression pattern and mitochondrial/peroxisomal enzyme activities in response to high fat diet (HFD) and clofibrate, a well known PPARalpha ligand.

MATERIALS AND METHODS

Four groups of Wistar-Albino rats were included: (1) rats fed a control diet (CD) for 6 weeks, (2) rats fed CD (6 weeks) plus clofibrate (last 2 weeks), (3) rats fed HFD for 6 weeks, and (4) rats fed HFD (6 weeks) plus clofibrate (last 2 weeks). Peroxisome proliferator-activated receptor alpha expression was evaluated by immunohistochemistry. Fatty acid beta-oxidation (peroxisomal-acyl-CoA-oxidase and mitochondrial-acyl-CoA-dehydrogenase) and catalase enzyme activities, and malondialdehyde and glutathion levels were measured spectrophotometrically in liver tissues.

RESULTS

All animals were fed HFD but only 2/12 animals were fed HFD plus clofibrate-developed fatty liver. Both HFD and clofibrate induced PPARalpha expression, clofibrate induction being more prominent than HFD. Clofibrate plus HFD did not further increase PPARalpha expression. Activities of peroxisomal-acyl-CoA-oxidase and mitochondrial-acyl-CoA-dehydrogenase enzymes were not induced by HFD alone. Clofibrate increased the activity of these enzymes in both CD- and HFD-fed animals. However, an increase of acyl-CoA-oxidase activity was blunted in rats fed HFD. Catalase activity and malondialdehyde levels were increased but glutathion levels were unchanged in rats fed HFD plus clofibrate.

CONCLUSIONS

Clofibrate was a more potent inducer of PPARalpha expression than HFD in our rat fatty liver model. The finding of blunted peroxisomal enzyme response to clofibrate in fatty livers suggests that alterations in postreceptor events may exist and further contribute to liver steatosis. Clofibrate seems to stabilize glutathion content and this might contribute to the prevention of liver steatosis.

YSDD: a novel mutation in HBV DNA polymerase confers clinical resistance to lamivudine

The emergence of drug-resistant virus in hepatitis B virus (HBV) patients treated with lamivudine is well documented. In this study, we determined the mutations occurring in the tyrosine-methionine-aspartate-aspartate (YMDD) amino acid motif of the HBV DNA polymerase gene, as well as upstream and downstream of this region, in patients with breakthrough virus during lamivudine therapy. Thirty-one Turkish patients (20 patients HBeAg positive, 11 patients HBeAg negative and anti-HBe positive) with chronic HBV infection who completed at least 104 weeks of lamivudine treatment were investigated. All patients received lamivudine, (150 mg/day), for 104 weeks, with or without 4 months of interferon (IFN) combination. HBV-specific sequences were amplified by polymerase chain reaction (PCR) from sera of patients with breakthrough virus, and the PCR products were directly analysed by sequencing. Breakthrough virus was detected in seven of the 31 patients (22.6%) between 9 and 18 months of therapy. Of the seven patients, six were HBeAg positive at baseline, and four had a double mutation consisting of rtM204V and rtL180M, while two had an rtM204I change. In one patient, two base substitutions at rt204 (ATG --> AGT; T to G and G to T) lead to a methionine to serine change (YMDD --> YSDD). This novel DNA pol mutation was detected at month 18 of lamivudine treatment. In addition, this new variant had the rtL180M mutation and a 12 base pair deletion in the pre-S1 region between nucleotides 43-54. The YSDD mutation was still present 6 months after lamivudine discontinuation. In vitro transfection studies also confirmed that the YSDD strain is resistant to lamivudine. In conclusion, the results indicate that, in addition to a Met --> Val and Met --> Ile change in YMDD, a Met --> Ser change at rt204 (YMDD --> YSDD) associated with the rtL180M change can also emerge during lamivudine treatment, which confers lamivudine resistance in vivo and in vitro, leading to virological breakthrough and ALT increases.

The central opioid system in liver disease and its complications

The best known example of an interaction between the liver and the brain is hepatic encephalopathy. In the 90s a central nervous system origin of the pruritus of cholestatic liver disease and more recently of fatigue of liver disease has been suggested. Hence, three important manifestations of liver disease may be of central origin. Evidence is accumulating that the central opioid system is involved in the development of these manifestations. This short review summarizes current knowledge on the role of the opioid system in development of these liver disease manifestations.

Risk factors for hepatocellular carcinoma in Turkey

The contribution of hepatitis B, hepatitis C, and excess alcohol intake to the development of hepatocellular carcinoma in Turkey was assessed. The study was conducted through a questionnaire sent to seven major medical referral centers in different regions of Turkey and is based on 207 patients seen in the period 1994-1997. Of the seven centers, two were located in West Turkey (54 patients), two were in Central Turkey (85 patients), and two were in south and southeast Turkey (68 patients). In 196 of the 207 patients (94.7%), there was a history of chronic liver disease, and in 180 patients (87%) liver cirrhosis was documented. Of the 207 patients, 116 (56%) had hepatitis B, 48 (23.2%) had hepatitis C, and 33 (15.9%) had a history of excess alcohol intake. Anti-delta testing was available in 69 of 116 patients with hepatitis B, and anti-HDV was positive in 13 of these patients (13/69, 18.8%). Of the 33 patients with a history of heavy alcohol intake, 18 had concomitant chronic viral hepatitis infection, and alcohol alone was the etiology of hepatocellular carcinoma in only 15 cases (7.2%). The distribution of etiologic factors was not homogenous in different geographical regions in Turkey. In central, south, and southeastern Turkey, the predominant etiology of hepatocellular carcinoma was hepatitis B, whereas in western Turkey the impact of hepatitis B, hepatitis C, and alcohol was similar. This study indicates that hepatitis B virus infection is the leading cause of hepatocellular carcinoma in Turkey, followed by hepatitis C infection and alcoholic liver disease.

Nucleotide divergences in the core promoter and precore region of genotype D hepatitis B virus in patients with persistently elevated or normal ALT levels

BACKGROUND

Mutation in the hepatitis B virus precore codon 28, creating a translational stop codon and double 1762-1764 T/A mutations in the core promoter region, controlling the transcription of the precore RNA and the core RNA have been suggested to correlate with the HBeAg status of patients with HBV infection.

OBJECTIVES

The aim of the study was to further investigate the association of nucleotide divergences in both core promoter and precore regions with liver cell injury (reflected by ALT levels) in patients with chronic HBV infection.

STUDY DESIGN

The sequences of the core promoter and the precore region of HBV isolated from 67 patients, all having genotype D and subtype ayw were analyzed. The patients were divided into two groups and four subgroups according to their HBeAg and Anti-HBe status, and ALT profile.

RESULTS

It was found that the nucleotide divergences in the core promoter but not in the precore region were higher in patients having persistently elevated serum ALT than in serum ALT normal patients in both HBeAg positive and Anti-HBe positive groups (P<0.05). The number of T/A and A1896 stop codon mutations did not yield a statistically significant difference between ALT normal and elevated groups. It was also found that 1762-1764 T/A and precore A 1896 mutation existed in five and six out of 29 HBeAg positive patients, respectively. In 38 anti-HBe positive patients, 1762-1764 T/A and precore A1896 mutation were detected in three and 16 patients respectively, and coexisted in 10 patients.

CONCLUSIONS

Precore A 1896 stop codon mutation seems to play an essential role in the loss of HBeAg in Turkish patients. Serum viremia levels of HBV in patients having precore stop codon and/or T/A mutation were not significantly different from the other patients carrying wild type strains. Nucleotide variability in the core promoter region may be one of the factors linked to hepatitis B disease activity.

Circulating IL-2, IL-10 and TNF-alpha in chronic hepatitis B: their relations to HBeAg status and the activity of liver disease

BACKGROUND/AIMS

Preferential production of immunoregulatory cytokines may play an important role in the pathogenesis of chronic hepatitis B. We aimed to determine the serum levels of IL-2, IL-10 and TNF-alpha in patients with chronic hepatitis B and to correlate these findings with the activity of liver disease, HBeAg/anti-HBe status and replication level of the virus.

METHODOLOGY

Seventy-two chronic hepatitis B patients were categorized into 4 groups according to activity of liver disease and HBeAg status. Group 1 (n = 13): HBeAg and HBV DNA-positive with persistently normal ALT. Group 2 (n = 20): HBeAg and HBV DNA-positive patients with persistently elevated ALT. Group 3 (n = 19): HBeAg and HBV DNA-negative patients with persistently normal ALT. Group 4 (n = 20): HBeAg-negative patients with persistently elevated ALT and variable serum HBV DNA. IL-2, IL-10 and TNFa levels were determined in stored patient sera.

RESULTS

Apart from group 1 patients, all patients groups had higher IL-2 levels compared to controls suggesting that IL-2 production is increased when liver disease becomes active in HBeAg-positive phase of HBV infection. Only group 2 patients had elevated IL-10 levels compared to controls. None of the HBeAg-negative patients had detectable TNF-alpha levels while 64% HBeAg-positive patients had elevated levels of TNF-alpha irrespective of the activity of liver disease. Except TNF-alpha, no association was found between HBV DNA status and the presence or absence of detectable cytokines in circulation.

CONCLUSIONS

Our results suggest that circulating cytokine profile in chronic hepatitis B is related with the HBeAg status, replication level of the virus and the activity of liver disease.

Circulating IL-2 and IL-10 in chronic active hepatitis C with respect to the response to IFN treatment

BACKGROUND

The importance of circulating immunoregulatory cytokines in response to IFN treatment and the change of in vivo production of these cytokines during interferon (IFN) treatment are not well known. We aimed to determine whether pretreatment serum levels of IL-2 and IL-10 are predictive of the response to IFN treatment and to investigate if treatment response or nonresponse has any effect on the circulating levels of these cytokines.

PATIENTS AND METHODS

37 patients (18 responders and 19 non-responders) with chronic hepatitis C virus (HCV) infection who received IFN-alpha2b for 6 months were studied. Responders were defined by complete alanine aminotransferase (ALT) normalization and loss of HCV RNA as detected by bDNA assay while patients who had elevated ALT levels and positive HCV RNA after 6 months were considered as nonresponders.

RESULTS

Genotype distribution, ALT and HCV RNA levels were similar in responders and nonresponders. A significant number of patients with chronic hepatitis C (20/37 = 54%) had elevated IL-2 levels while IL-10 levels were not different from controls. No difference in baseline cytokine levels was observed between responders and non-responders. In the posttreatment serum samples some patients lost their detectable IL-2 or IL-10; some patients developed detectable cytokine levels after treatment irrespective of the treatment response.

CONCLUSION

These results suggest that active liver injury in chronic hepatitis C is associated with increased circulating Th1 cytokine IL-2 but not with Th2 cytokine IL-10 and that circulating levels of these cytokines do not predict the response to IFN treatment. There is no constant and regular change in circulating levels of these cytokines under IFN treatment with respect to treatment response.

Influence of viral load and alanine aminotransferase on viral genetic heterogeneity in patients with chronic hepatitis C virus infection

BACKGROUND/AIM

Hepatitis C virus (HCV) populations in vivo consist of genetically different heterogeneous mixtures defined as 'quasispecies', which vary in the hypervariable region 1 (HVR1) mostly. To further address the role of quasispecies diversity in hepatitis C infection, this study aimed to evaluate the influence of ALT, viral load and genotypes on quasispecies heterogeneity in patients with HCV infection.

METHODS

Thirty-six chronic hepatitis C patients with high levels of alanine aminotransferase (ALT) were studied. None of them received any antiviral therapy. HCV RNA serum levels, genotype and genetic heterogeneity were determined by branched-chain DNA assay, restriction fragment length patterns and RT-PCR single-strand conformational polymorphism analysis of HVR1, respectively.

RESULTS

Twenty-eight patients had genotype 1b (28/36; 78%), 6 patients had genotype 1a (6/36; 17%), 1 patient was 2a (1/36; 3%) and genotype could not be determined in 1 patient. The patients were categorized into two groups according to the number of bands representing the dominant strains in the circulation: group A with 2 bands having 1 strain (14/36 patients; 39%) and group B with more than 2 bands indicating more than 1 strain (22/36 patients; 61%). The serum viremia and ALT levels for these groups were 11 +/- 8.8 and 5.3 +/- 4.6 mEq/ml (p < 0.05), and 79 +/- 20, and 127 +/- 80 IU/l (p < 0.05), respectively.

CONCLUSION

The results of this study suggest that hepatitis C patients having 1 dominant strain in the circulation may show a relatively weaker immune response resulting in lower ALT and higher viremia levels, whereas patients with high degrees of virus quasispecies diversity have higher ALT levels and a more active immune response causing the selection of new genome variants and depressing viral replication partly.

Combination treatment of hepatic encephalopathy due to thioacetamide-induced fulminant hepatic failure in the rat with benzodiazepine and opioid receptor antagonists

BACKGROUND/AIMS

Treatment of hepatic encephalopathy with drugs acting on the target organ of this syndrome, the brain, is unsatisfactory. Combination treatment with different neurotransmitter receptor antagonists may be a rational option to optimize treatment.

METHODS

The effects of various doses of the benzodiazepine receptor antagonist Ro 15-3505 and the opioid receptor antagonist naloxone, alone or in combination, were tested on hepatic encephalopathy in rats with thioacetamide-induced hepatic failure in an open-field activity meter. Comparison of single and combination treatment was also done using a neurological test battery. In addition, we compared survival of treatment-responder rats with treatment non-responders.

RESULTS

Naloxone dose dependently increased ambulatory activity and improved neurological score. Ro 15-3505 also improved ambulatory activity and neurological score; however, the improvement was less evident at higher doses. Combination treatment was not superior to single treatment. Survival was increased in treatment-responder rats.

CONCLUSIONS

The failure of combination treatment with Ro 15-3505 and naloxone to further improve hepatic encephalopathy may suggest that the two neurotransmitter systems are interrelated or that hepatic encephalopathy may not be further improved by drugs acting on the brain.

Serum cytotoxin and oxidant stress markers in N-acetylcysteine treated thioacetamide hepatotoxicity of rats

N-acetylcysteine (NAC) is a glutathione precursor used to treat several clinical conditions where intracellular oxidant-antioxidant balance is disturbed, among which, acetaminophen induced hepatotoxicity may be counted. In this study, administering thioacetamide (TAA) as a hepatotoxic agent, a rat model of hepatotoxicity has been established, to investigate some of the immune mediated basic oxidant-antioxidant homeostatic mechanisms involved, and potential serum markers for follow-up of disease and treatment. To do this, four experimental groups receiving saline/saline, saline/NAC, saline/TAA and NAC/TAA as intraperitoneal injections, have been formed. Rat serum tumor necrosis factor-alpha (TNF-alpha), Interleukin1-beta (IL1-beta), malondialdehyde (MDA) as a measure of final oxidant damage and the antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) have been assayed. Hepatocellular damage has been measured via the biochemical estimates ALT, AST and LDH as well as histopathological grading. It was found that both TNF-alpha and IL1-beta were significantly elevated in saline/TAA receivers (P<0.01) when compared to NAC/TAA receivers. Serum MDA was also increased in TAA receivers in addition to SOD (P<0.05) and GSH-Px (P<0.05). Serum nitrite levels have also been assayed to give an estimate of nitric oxide that is suggested as a counter-balancer of oxidant stress. NAC/saline receivers had the highest levels of nitrites in the serum (P<0.05). Our results indicate that part of the hepatocellular injury to rat liver, induced by TAA is mediated by oxidative stress caused by the action of cytokines imparted by the enzymatic SOD and GSH-Px and non-enzymatic gaseous nitric oxide mechanisms causing an alleviation on administration of NAC. In addition, TNF-alpha, IL1-beta, MDA, SOD, GSH-Px and nitrites are potential candidates of serum indicators for monitorization of pathophysiological stage of liver disease.

Hereditary pancreatitis: report of a family from Turkey

Chronic pancreatitis is a rare disease in children and is usually secondary to underlying diseases such as hereditary pancreatitis, cystic fibrosis, hyperlipidemia, prolonged malnutrition, gallstones or anomalies of the biliary-pancreatic duct system. Hereditary pancreatitis is a common cause of chronic pancreatitis in children but is often unrecognized until months or years later. We report here a family with hereditary pancreatitis in which four members are affected.

Opioid receptor ligands in human hepatic encephalopathy

BACKGROUND/AIMS

Opioid peptides may contribute to some of the manifestations of hepatic encephalopathy. To address the role of the opioid system in the pathogenesis of hepatic encephalopathy, three representative opioid ligands were measured in plasma and cerebrospinal fluid of patients with hepatic encephalopathy.

METHODS

Plasma and cerebrospinal fluid were obtained in three groups of patients: group 1: patients with hepatic encephalopathy; group 2: patients with lumbar back pain; group 3: healthy controls. Met-enkephalin, leu-enkephalin and beta-endorphin levels were measured in extracted plasma and cerebrospinal fluid samples by radioimmunoassay.

RESULTS

Plasma met-enkephalin levels were 656% (p<0.05) and 301% (p<0.05) and cerebrospinal fluid met-enkephalin levels were 1481% (p<0.01) and 645% (p<0.05) higher when compared to healthy control and pain control patients, respectively. Although plasma and cerebrospinal leu-enkephalin levels were elevated in patients with hepatic encephalopathy, the increases were not statistically significant. Plasma and cerebrospinal beta-endorphin levels were similar in the three study groups.

CONCLUSIONS

The results of this study support accumulating data on the role of the delta opioid receptor ligand met-enkephalin in the pathogenesis of hepatic encephalopathy, and provide a rationale for the use of opioid receptor antagonists in the treatment of hepatic encephalopathy.

Effect of inhibition of ornithine decarboxylase activity in a model of acute hepatocellular necrosis

OBJECTIVE

The effect of blockade of the enzyme ornithine decarboxylase by difluoromethylornithine (DFMO) on hepatocellular necrosis and survival in rats treated with thioacetamide (TAA) was investigated.

DESIGN

In one experiment, the effect of DFMO on survival of rats with TAA-induced acute hepatocellular necrosis was determined. In another experiment, blood and liver specimens were obtained from DFMO or saline-treated rats 24 h after the administration of TAA for determinations of serum alanine aminotransferase (ALT) and liver content of polyamines and microsomal cytochrome P-450 and for assessment of hepatic histology.

METHODS

Liver polyamines were determined by reversed-phase HPLC and microsomal cytochrome P-450 content by dithionite-difference spectroscopy of CO-treated homogenates. The severity of hepatocellular necrosis was scored blindly.

RESULTS

TAA-treated rats that received DFMO survived longer than saline-treated controls (P < 0.01). Serum ALT and liver putrescine concentrations were lower and the histological severity of acute hepatocellular necrosis was less in DFMO-treated rats with TAA-induced hepatocellular necrosis than in saline-treated controls (P < 0.05, P < 0.01 and P < 0.05, respectively). Total cytochrome P-450 levels were similar in DFMO and saline-treated rats with TAA-induced hepatocellular necrosis.

CONCLUSIONS

DFMO increases survival in TAA-induced fulminant hepatic failure by decreasing the severity of acute hepatocellular necrosis. The beneficial effects of DFMO do not appear to be mediated by its effects on polyamine metabolism, but may be attributable to an effect of DFMO on thioacetamide metabolism or on an alternative pathway of ornithine metabolism.

Modulation of hepatic encephalopathy in rats with thioacetamide-induced acute liver failure by serotonin antagonists

OBJECTIVE

Accumulated neurochemical data in different animal models of fulminant hepatic failure and in humans with hepatic encephalopathy suggest that serotoninergic tone is increased in the brain in hepatic encephalopathy. Since neurochemical alterations may not have behavioural or electrophysiological consequences the contribution of the serotoninergic system to the pathogenesis of hepatic encephalopathy was explored.

METHODS

The effects of drugs modulating serotoninergic neurotransmission, the nonselective serotonin receptor antagonist methysergide and the serotonin2 receptor antagonist seganserin were tested neuropharmacologically in thioacetamide-induced acute liver failure in rats.

RESULTS

Methysergide had no effect in control rats, but dose dependently increased motor activity in stage II-III hepatic encephalopathy by 232% (5 mg/kg methysergide), 531% (10 mg/kg) and 507% (20 mg/kg). In contrast, seganserin had no effect in encephalopathic rats.

CONCLUSION

It is suggested that the beneficial effects of methysergide are serotonin, receptor mediated. Overall the results suggest that serotoninergic mechanisms contribute to some of the behavioural manifestations of hepatic encephalopathy in this animal model.

Ribavirin as therapy for chronic hepatitis C. A randomized, double-blind, placebo-controlled trial

OBJECTIVE

To evaluate ribavirin, an oral antiviral agent, as therapy for chronic hepatitis C.

DESIGN

Randomized, double-blind, placebo-controlled study.

SETTING

Clinical Center of the National Institutes of Health, a tertiary referral research hospital.

PATIENTS

29 patients with chronic hepatitis C who received oral ribavirin (600 mg twice daily) for 12 months and 29 controls with chronic hepatitis C who received placebo for 12 months.

MEASUREMENTS

Effects of therapy were evaluated by measuring serum aminotransferase and hepatitis C virus (HCV) RNA levels before, during, and for 6 months after therapy and by histologic examination of liver specimens before and at the end of treatment.

RESULTS

Patients treated with ribavirin had a prompt decrease in serum aminotransferase levels (54% overall) compared with levels before treatment and levels in controls (5% decrease). Serum aminotransferase levels became normal or nearly normal in 10 patients treated with ribavirin (35% [95% CI, 18% to 54%]) but in no controls (0% [CI, 0% to 12%]). Aminotransferase levels remained normal in only 2 patients after ribavirin therapy was discontinued (7% [CI, 1% to 23%]). Serum HCV RNA levels did not change during or after therapy. Liver biopsy specimens showed a decrease in hepatic inflammation and necrosis among ribavirin-treated patients whose aminotransferase levels became normal.

CONCLUSIONS

Ribavirin has beneficial effects on serum aminotransferase levels and histologic findings in the liver in patients with chronic hepatitis C, but these effects are not accompanied by changes in HCV RNA levels and are not sustained when ribavirin therapy is discontinued. Thus, ribavirin alone for periods as long as 12 months is unlikely to be of value as therapy for chronic hepatitis C.

Effects of naloxone infusions in patients with the pruritus of cholestasis. A double-blind, randomized, controlled trial

OBJECTIVE

To determine whether endogenous opioids contribute to the pruritus of cholestasis by studying the effect of the opiate antagonist naloxone on the perception of pruritus and on scratching activity in patients with this form of pruritus.

DESIGN

Double-blind, placebo-controlled, crossover trial with four periods.

SETTING

Clinical research referral center.

PATIENTS

29 pruritic patients with liver diseases of various causes.

INTERVENTION

Each patient received as many as two naloxone and two placebo solution infusions consecutively in random order. Each infusion lasted 24 hours.

MEASUREMENTS

During the infusions, visual analog scores of pruritus were recorded every 4 hours while patients were awake; scratching activity independent of limb movements was recorded continuously.

RESULTS

One patient had a mild reaction consistent with a naloxone-precipitated syndrome similar to opiate withdrawal. A significant 24-hour rhythm of scratching activity was seen in 7 of 11 patients for whom complete 96-hour data were collected. The mean of a visual analog score of the perception of pruritus (maximum, 10.0) recorded during naloxone infusions was 0.582 lower than that recorded during placebo infusions (95% CI, 0.176 to 0.988; P < 0.01). Furthermore, the ratio of the geometric mean hourly scratching activity during naloxone infusions to that during placebo infusions was 0.727 (CI, 0.612 to 0.842; P < 0.001) and was greater than 1.0 in only five patients.

CONCLUSIONS

Naloxone administration is associated with amelioration of the perception of pruritus and reduction of scratching activity in cholestatic patients. Because of the opioid receptor specificity of the action of naloxone, these findings support the hypothesis that a mechanism underlying the pruritus of cholestasis is modulated by endogenous opioids and suggest that opiate antagonists may have a role in the management of this complication of cholestasis.

Gut bacteria provide precursors of benzodiazepine receptor ligands in a rat model of hepatic encephalopathy

Benzodiazepine receptor (BZR) ligands are elevated in animals and humans with fulminant hepatic failure (FHF) and contribute to the pathogenesis of the associated hepatic encephalopathy (HE). As gut factors are proposed to play a role in the pathogenesis of HE, we investigated gut flora as a source of BZR ligands. Rats received daily oral neomycin, vancomycin and metronidazole (AB +) or saline (AB -) before and concurrent with the induction of FHF with thioacetamide. BZR ligands were extracted from brain and plasma and quantified using radiometric techniques. Plasma BZR ligand concentrations in AB(+) and AB(-) rats with HE were higher than AB(+) and AB(-) control rats. Brain BZR ligand concentrations increased in AB(+) and AB(-) rats with HE. Stool cultures from antibiotic treated rats with HE indicated the presence of multidrug resistant Acinetobacter lwoffii. Although no significant concentrations of BZR ligands were detected in culture media inoculated with A. lwoffii, administering A. lwoffii to normal rats significantly elevated BZR ligand levels in brain, but not plasma. Thus, antibiotic treatment of rats is associated with the growth of a resistant strain of bacterium which produces an inactive BZR ligand precursor. BZR ligands may be synthesized from these precursors in the brain and efficiently cleared by a normal liver following brain-to-plasma transfer. Impairment of this clearance process in FHF facilitates their accumulation, enabling agonist BZR ligands to contribute to the pathogenesis of HE by further enhancing GABAergic neurotransmission.

Brain and plasma levels of opioid peptides are altered in rats with thioacetamide-induced fulminant hepatic failure: implications for the treatment of hepatic encephalopathy with opioid antagonists

Although plasma levels of Met-enkephalin and beta-endorphin are elevated in patients suffering from liver failure, it is not known whether central nervous system (CNS) opioidergic neurotransmission is altered in these patients. Such changes may contribute to the motor dysfunction, psychiatric abnormalities and CNS depression observed in hepatic encephalopathy (HE). Therefore, Met- and Leu-enkephalin, dynorphin A and beta-endorphin levels were measured in discrete brain regions and plasma from thioacetamide-treated rats in Stages II to IV of HE. Pituitary and plasma beta-endorphin, Met- and Leu-enkephalin concentrations increased with the severity of HE by 50 to 290%. Pituitary and brainstem dynorphin A levels increased whereas plasma levels decreased in rats with thioacetamide-induced fulminant hepatic failure. Both striatal Met- and Leu-enkephalin levels increased and hypothalamic concentrations decreased in HE. Concurrent with the increase in striatal Met-enkephalin levels was a 26 to 48% decrease in the density of striatal and hypothalamic delta receptors. No change in either the density or affinity of radioligand binding to mu or delta receptors was observed in the CNS. Finally, administering (+/-)-naloxone (5 and 10 mg/kg) or (+/-)-naltrexone (5-15 mg/kg), but not (+)-naloxone (10 mg/kg), significantly increased the motor activity of rats with Stage III HE. Whereas elevated plasma levels of opioid peptides may play a role in the peripheral manifestations of hepatic failure (ascites and hypotension), increased CNS levels of these peptides may be involved in the neuropsychiatric abnormalities characteristic of HE. Thus, opioid antagonists may be effective in ameliorating some of the neurological manifestations of HE.

Benzodiazepine receptor ligands are elevated in an animal model of hepatic encephalopathy: relationship between brain concentration and severity of encephalopathy

Elevated levels of benzodiazepine receptor agonists are found in both animal models of hepatic encephalopathy and in humans with this syndrome. The present study investigated the relationship between agonist levels and the severity of the encephalopathy, as well as the potential reversibility of the syndrome by benzodiazepine receptor antagonists. The concentrations of benzodiazepine receptor ligands in rat brains were measured at several intervals during the induction of liver failure with thioacetamide. Six hours after the first dose of thioacetamide, brain concentrations of benzodiazepine receptor ligands were increased and open field activity decreased compared to control rats. However, the brain concentrations of benzodiazepine receptor ligands correlated better with the stage of hepatic encephalopathy than time after initiation of thioacetamide treatment. The benzodiazepine receptor ligands Ro 15-3505, Ro 15-4513 and CGS-8216 ameliorated motor abnormalities in rats with stage 3 hepatic encephalopathy. Only Ro 15-3505 improved motor activity in rats in stage 2 encephalopathy to levels observed in rats with stage 1 encephalopathy. Furthermore, although Ro 15-4513 and CGS 8216 significantly increased motor activity in stage 4 hepatic encephalopathy, this may reflect their partial inverse agonist properties. These findings support the hypothesis that increased brain levels of benzodiazepine receptor agonists contribute to the severity of hepatic encephalopathy and suggest that high-affinity benzodiazepine receptor antagonists are efficacious in reversing this syndrome.

Do benzodiazepine ligands contribute to hepatic encephalopathy?

1. Levels of BZ receptor ligands are elevated in the brain of animal models of FHF and humans with FHF. Some of these ligands have agonist properties and some are known 1, 4-BZs which bind to the DS receptor. Much of the BZ receptor ligand activity in HE is unidentified and it is possible that some may bind to receptor subtypes other than the DS receptor. 2. Average levels of BZ receptor ligands in the brain in HE do not appear to be sufficient to augment GABAergic tone to a degree that would result in severe encephalopathy (i.e. coma). However, these ligands have a heterogeneous distribution in the brain and their neuroinhibitory effects may be potentiated by increased availability of GABA at GABAA receptors. Furthermore, that these ligands may contribute to HE is suggested by anecdotal reports of ameliorations of HE being induced in a majority of patients by the BZ receptor antagonist flumazenil. 3. The response of HE to flumazenil in humans is usually incomplete and in animal models may be modest. Potential explanations for these findings include pharmacokinetics, BZ receptor subtype specificity and higher levels of BZ receptor ligands in the brain in humans with HE than in animal models. 4. Certain BZ receptor ligands e.g. Ro 15-3505 and Ro 15-4513, that are structurally related to flumazenil, are more efficacious at ameliorating HE than flumazenil in animal models. These findings may be more dependent on differences in BZ receptor subtype specificity than differences in intrinsic activity. The properties of an ideal BZ receptor ligand for administration to a patient with HE would appear to be: (i) antagonist action at BZ receptors, (ii) no intrinsic activity apparent after a conventional pharmacologic dose, (iii) high specificity and affinity for BZ receptors, (iv) slow metabolism, and (v) absence of toxic effects. Promising ligands, such as Ro 15-3505, with weak partial inverse agonist actions and hence analeptic potential, require careful evaluation of their therapeutic index before clinical application. 5. BZ receptor ligands may be useful in the management of HE. Specifically, they may be given IV: (i) to reverse effects of exogenous BZs; (ii) to aid in the differential diagnosis of encephalopathy; (iii) to provide prognostic information; and (iv) to optimize brain function. They may also be given orally with the objective of reducing dietary protein intolerance in patients with chronic liver disease.

[Parasite prevalence in schools with different socioeconomic status and evaluation of methods for diagnosing intestinal parasitic diseases]

In this study; the parasite prevalence of schools with different socio-economical status and three methods for diagnosing intestinal parasitosis were evaluated. Children from two primary schools and one junior high school with different socio-economical status participated in the study. The three method used for diagnosing parasitosis in this study were direct wet mounts, concentrated saline flotation technique, and zinc sulfate centrifugal flotation method. Parasitosis was found in 69 fecal samples (18%). The distribution of the parasites found were Hymenolepis nana (29%), Ascaris lumbricoides (26%), Enterobius vermicularis (23%), Trichirus trichiura (18%), taenia saginata (4%). The parasite prevalence in schools with low and high socioeconomical status differed significantly (27% vs. 5% respectively). Combined methods were superior to single methods. The combined method of direct wet mounts and zinc sulfate centrifugal flotation was the most sensitive method (diagnosis rate 90%). But we think that the combined method of direct wet mounts and concentrated saline flotation technique is a simpler method with almost equal results (86%).

Increased serotoninergic and noradrenergic activity in hepatic encephalopathy in rats with thioacetamide-induced acute liver failure

Functional changes of various neurotransmitter systems have been implicated in the pathogenesis of hepatic encephalopathy. In this study the role of brain monoaminergic neurotransmitter systems in hepatic encephalopathy was investigated in rats with thioacetamide-induced acute liver failure. Concentrations of serotonin, dopamine, noradrenaline and of their metabolites 5-hydroxyindoleacetic acid, dihydroxyphenylalanine (following inhibition of dihydroxyphenylalanine-decarboxylase), dihydroxyphenylacetic acid, homovanillic acid and 3-methoxy-4-hydroxyphenyl-glycol, were measured in the cerebral cortex, striatum and hippocampus by high performance liquid chromatography with electrochemical detection. In hepatic encephalopathy concentrations of 5-hydroxyindoleacetic acid were increased in all three brain areas (196%, 204% and 264% of saline-treated controls, p less than 0.01), and concentrations of serotonin were increased in the frontal cortex (121%, p less than 0.01). In the frontal cortex and hippocampus of encephalopathic rats dopamine levels were increased (157% and 289%, p less than 0.05), and levels of noradrenaline (53% and 46%, p less than 0.05) were decreased associated with increased 3-methoxy-4-hydroxyphenylglycol levels (173% and 206%, p less than 0.05). The extent of these changes correlated with the stage of hepatic encephalopathy. In hepatic encephalopathy dihydroxyphenylalanine accumulation was increased in the hippocampus and unchanged in the cerebral cortex. Dopamine, noradrenaline, dihydroxyphenylacetic acid and homovanillic acid concentrations were unchanged in the striatum. The results of this study indicate that hepatic encephalopathy in thioacetamide-induced acute liver failure in rats is associated with neurochemical changes, suggesting an increased activity of the noradrenergic and serotoninergic neurotransmitter systems.

Hepatic encephalopathy in thioacetamide-induced acute liver failure in rats: characterization of an improved model and study of amino acid-ergic neurotransmission

An imbalance of excitatory and inhibitory amino acid-ergic neurotransmission has been suggested to play a role in the pathogenesis of hepatic encephalopathy. For further evaluation of this hypothesis, several parameters of amino acid-ergic neurotransmission were studied in rats with acute liver failure induced by the administration of 300 mg per kg thioacetamide by gavage on two consecutive days. By appropriate supportive care, hypoglycemia, renal failure and hypothermia were avoided. Rats were monitored clinically and neurologically. Hepatic encephalopathy evolved in four distinct, easily recognizable stages. Light and electron microscopic examination of brains of rats with hepatic encephalopathy revealed only a slight swelling of nuclei of neurons and astrocytes without signs of neuronal degeneration or brain edema. In rats with hepatic encephalopathy, the concentrations of GABA, glutamate and taurine were decreased in the cerebral cortex, the hippocampus and the striatum, whereas those of aspartate and glycine were unchanged or increased. GABAA and benzodiazepine receptors were studied as parameters for the postsynaptic GABAA-benzodiazepine receptor complex, glutamic acid decarboxylase as parameter for presynaptic GABA-ergic neurons and stimulation of benzodiazepine binding by GABA as a parameter for a GABA-mediated postsynaptic event. None of these parameters was different in hepatic encephalopathy as compared to controls. Similarly, Ca++/Cl(-)-dependent and -independent glutamate receptors as parameters for glutamatergic neurons were unchanged in rats with hepatic encephalopathy. Thus, in rats with thioacetamide-induced liver failure and hepatic encephalopathy, changes of the concentrations of neurotransmitter amino acids occur in the brain. Other neurochemical parameters, however, failed to identify alterations of GABA-ergic or glutamatergic neurotransmission in hepatic encephalopathy.